Re: Multiple disjoint sample sets?
Roy Smith wrote: > I have a list of items. I need to generate n samples of k unique items > each. I not only want each sample set to have no repeats, but I also > want to make sure the sets are disjoint (i.e. no item repeated between > sets). > > random.sample(items, k) will satisfy the first constraint, but not the > second. Should I just do random.sample(items, k*n), and then split the > resulting big list into n pieces? Or is there some more efficient way? > > Typical values: > > len(items) = 5,000,000 > n = 10 > k = 100,000 I would expect that your simple approach is more efficient than shuffling the whole list. Assuming there is a sample_iter(population) that generates unique items from the population (which has no repetitions itself) you can create the samples with g = sample_iter(items) samples = [list(itertools.islice(g, k) for _ in xrange(n)] My ideas for such a sample_iter(): def sample_iter_mark(items): n = len(items) while True: i = int(random()*n) v = items[i] if v is not None: yield v items[i] = None This is destructive and will degrade badly as the number of None items increases. For your typical values it seems to be OK though. You can make this non-destructive by adding a bit array or a set (random.Random.sample() has code that uses a set) to keep track of the seen items. Another sample_iter() (which is also part of the random.Random.sample() implementation): def sample_iter_replace(items): n = len(items) for k in xrange(n): i = int(random()*(n-k)) yield items[i] items[i] = items[n-k-1] You can micro-optimise that a bit to avoid the index calculation. Also, instead of overwriting items you could swap them, so that no values would be lost, only their initial order. -- http://mail.python.org/mailman/listinfo/python-list
Re: problem with exam task for college
sorry for the extremely late reply, i have been very very busy :s i implemented the solution that was posted in the second to last post. but now it gets a little confusing because i think a couple terms where deleted that i refered to in other code blocks, so once again i''l post the full code here from visual import * import time import math import random from datetime import datetime import operator class lunar_lander(object): def __init__(self): scene.title = 'mini star wars' scene.width = 375 scene.height = 550 scene.center = (0,0) self.pos = (0,0) self.axis = 0 self.brandstofmeter = brandstofmeter() self.ruimteschip = ruimteschip() self.view = game_view(self) def play(self): t=0 dt=0.01 self.ruimteschip.updatemeter = False while t<9: time.sleep(0.01) self.ruimteschip.update(dt) t = t + dt if self.ruimteschip.updatemeter == True: self.brandstofmeter.update class game_view(object): def __init__(self,owner): autoscale=True box(pos=( 0, -375, 0), length=500, height=5, width=0, color = color.white) box(pos=(0,375, 0), length=500, height=5, width=0, color = color.white) box(pos=(-250,0, 0), length=5, height=750, width=0, color = color.white) box(pos=(250,0, 0), length=5, height=750, width=0, color = color.white) maan = curve(pos=[(-250,-353),(-240,-341),(-210,-354),(-199.5,-374)],color=color.red) maana = curve(pos=[(-199.5,-374),(-166,-374)],color=color.green) maanb = curve(pos=[(-166,-374),(-140,-357),(-80,-319),(-40,-361),(0,-321),(40,-329),(80,-347)],color=color.red) maanc = curve(pos=[(80,-347),(140,-347)],color=color.green) maand = curve(pos=[(140,-347),(162,-337),(189.5,-365),(210,-355),(240,-372),(250,-338)],color=color.red) for i in random.sample(range (-250,250),20): for j in random.sample(range (-375,375),20): sterren = points(pos = [i,j,0],size = 2, color=color.white) class brandstofmeter(object): def __init__(self): axis = 0 self.pos = (210,345) self.length = 25 self.height = 45 self.meter = box(pos = self.pos, length = self.length, height = self.height,color = color.green) def update(self): self.height = self.height - 0.2 print "ok" class ruimteschip(object): def __init__(self): self.pos = vector(0,330) self.acceleration = vector(0,-88,0) self.axis = (1,0,0) self.hoek = (90*math.pi)/180 self.graden = math.degrees(self.hoek) self.gas = vector(10 * cos(self.hoek),10 * sin (self.hoek)) self.velocity = vector(0,0,0) self.angle = pi / 2 self.updatemeter = False self.view = ruimteschip_view(self) self.vlam = self.view.vlam self.frame = self.view.frame self.zicht = brandstofmeter() def update(self,dt): self.velocity = self.velocity + (self.acceleration * dt) self.pos = self.pos + self.velocity * dt if scene.kb.keys: key = scene.kb.getkey() if key == "left": # Set left deviation self.frame.axis -= (0, 0, 0.05) self.gas = vector(-sin(self.angle), cos(self.angle)) elif key == "right": # Set right deviation self.frame.axis += (0, 0, 0.05) self.gas = vector(sin(self.angle), cos(self.angle)) elif key == "up": self.deviate() def deviate(self): # Set modified velocity self.frame.velocity += self.gas self.frame.pos += self.frame.velocity # Reset falling velocity self.frame.velocity -= self.gas if self.pos.x > 250: self.pos.x = -250 if self.pos.x < -250: self.pos.x = 250 self.view.update(self) class ruimteschip_view(object): def __init__(self,owner): self.owner = owner self.frame = frame(pos = owner.pos,axis = owner.axis) self.motor = curve(frame = self.frame,pos=[(0,24.0),(22.0,24.0),(22.0,39.0),(-22.0,39.0),(-22,24),(0,24)]) self.capsule = curve(frame = self.frame,color = color.blue ,pos=[(0,39),(-3,39),(-9,44),(-12,46),(-18,48),(-22,50),(-18,52),(-12,54),(-9,56),(-3,61),(0,61),(3,59),(9,56),(12,54),(18,52),(22,50),(18,48),(12,46),(9,44),(3,39),(0,39)]) self.poota = curve(frame = self.frame,pos = [(-18,24),(-20,24),(-20,0),(-18,0),(-18,24)]) self.pootb = curve(frame = self.frame,pos = [(18,24),(20,24),(20,0),(18,0),(18,24)]) self.vlam = curve(frame =
For Loop in List
Dear Group, I have a list like, >>> list1=[1,2,3,4,5,6,7,8,9,10,11,12] Now, if I want to take a slice of it, I can. It may be done in, >>> list2=list1[:3] >>> print list2 [1, 2, 3] If I want to iterate the list, I may do as, >>> for i in list1: print "Iterated Value Is:",i Iterated Value Is: 1 Iterated Value Is: 2 Iterated Value Is: 3 Iterated Value Is: 4 Iterated Value Is: 5 Iterated Value Is: 6 Iterated Value Is: 7 Iterated Value Is: 8 Iterated Value Is: 9 Iterated Value Is: 10 Iterated Value Is: 11 Iterated Value Is: 12 Now, I want to combine iterator with a slicing condition like >>> for i=list2 in list1: print "Iterated Value Is:",i So, that I get the list in the slices like, [1,2,3] [4,5,6] [7,8,9] [10,11,12] But if I do this I get a Syntax Error, is there a solution? If anyone of the learned members may kindly let me know? Apology for any indentation error,etc. Thanking You in Advance, Regards, Subhabrata -- http://mail.python.org/mailman/listinfo/python-list
Re: problem with exam task for college
corrected a bit, loop works, gas doesn't work from visual import * import time import math import random from datetime import datetime import operator class lunar_lander(object): def __init__(self): scene.title = 'mini star wars' scene.width = 375 scene.height = 550 scene.center = (0,0) self.pos = (0,0) self.axis = 0 self.brandstofmeter = brandstofmeter() self.ruimteschip = ruimteschip() self.view = game_view(self) def play(self): t=0 dt=0.01 self.ruimteschip.updatemeter = False while t<9: time.sleep(0.01) self.ruimteschip.update(dt) t = t + dt if self.ruimteschip.updatemeter == True: self.brandstofmeter.update class game_view(object): def __init__(self,owner): autoscale=True box(pos=( 0, -375, 0), length=500, height=5, width=0, color = color.white) box(pos=(0,375, 0), length=500, height=5, width=0, color = color.white) box(pos=(-250,0, 0), length=5, height=750, width=0, color = color.white) box(pos=(250,0, 0), length=5, height=750, width=0, color = color.white) maan = curve(pos=[(-250,-353),(-240,-341),(-210,-354),(-199.5,-374)],color=color.red) maana = curve(pos=[(-199.5,-374),(-166,-374)],color=color.green) maanb = curve(pos=[(-166,-374),(-140,-357),(-80,-319),(-40,-361),(0,-321),(40,-329),(80,-347)],color=color.red) maanc = curve(pos=[(80,-347),(140,-347)],color=color.green) maand = curve(pos=[(140,-347),(162,-337),(189.5,-365),(210,-355),(240,-372),(250,-338)],color=color.red) for i in random.sample(range (-250,250),20): for j in random.sample(range (-375,375),20): sterren = points(pos = [i,j,0],size = 2, color=color.white) class brandstofmeter(object): def __init__(self): axis = 0 self.pos = (210,345) self.length = 25 self.height = 45 self.meter = box(pos = self.pos, length = self.length, height = self.height,color = color.green) def update(self): self.height = self.height - 0.2 print "ok" class ruimteschip(object): def __init__(self): self.pos = vector(0,330) self.acceleration = vector(0,-88,0) self.axis = (1,0,0) self.hoek = (90*math.pi)/180 self.graden = math.degrees(self.hoek) self.gas = vector(10 * cos(self.hoek),10 * sin (self.hoek)) self.velocity = vector(0,0,0) self.angle = pi / 2 self.updatemeter = False self.view = ruimteschip_view(self) self.vlam = self.view.vlam self.frame = self.view.frame self.zicht = brandstofmeter() def update(self,dt): self.velocity = self.velocity + (self.acceleration * dt) self.pos = self.pos + self.velocity * dt if scene.kb.keys: key = scene.kb.getkey() if key == "left": # linkerafwijking self.frame.axis -= (0, 0, 0.05) self.gas = vector(-sin(self.angle), cos(self.angle)) self.vlam.visible = True self.updatemeter = True elif key == "right": # rechterafwijking self.frame.axis += (0, 0, 0.05) self.gas = vector(sin(self.angle), cos(self.angle)) elif key == "up": self.deviate() self.vlam.visible = False self.updatemeter = False if self.pos.x > 250: self.pos.x = -250 if self.pos.x < -250: self.pos.x = 250 self.view.update(self) def deviate(self): # zet veranderde snelheid self.frame.velocity += self.gas self.frame.pos += self.frame.velocity # Reset valsnelheid self.frame.velocity -= self.gas class ruimteschip_view(object): def __init__(self,owner): self.owner = owner self.frame = frame(pos = owner.pos,axis = owner.axis) self.motor = curve(frame = self.frame,pos=[(0,24.0),(22.0,24.0),(22.0,39.0),(-22.0,39.0),(-22,24),(0,24)]) self.capsule = curve(frame = self.frame,color = color.blue ,pos=[(0,39),(-3,39),(-9,44),(-12,46),(-18,48),(-22,50),(-18,52),(-12,54),(-9,56),(-3,61),(0,61),(3,59),(9,56),(12,54),(18,52),(22,50),(18,48),(12,46),(9,44),(3,39),(0,39)]) self.poota = curve(frame = self.frame,pos = [(-18,24),(-20,24),(-20,0),(-18,0),(-18,24)]) self.pootb = curve(frame = self.frame,pos = [(18,24),(20,24),(20,0),(18,0),(18,24)]) self.vlam = curve(frame = self.frame,color = color.orange , visible=false,pos = [(0,24.0),(-9.0,14.0),(0,-5.0),(9,14.0),(0,24.0)])
Re: For Loop in List
On 01/13/2013 07:45 AM, subhabangal...@gmail.com wrote: > Dear Group, > > I have a list like, > list1=[1,2,3,4,5,6,7,8,9,10,11,12] What version of Python? > Now, if I want to take a slice of it, I can. > It may be done in, list2=list1[:3] print list2 > [1, 2, 3] > > If I want to iterate the list, I may do as, > for i in list1: > print "Iterated Value Is:",i > > > Iterated Value Is: 1 > Iterated Value Is: 2 > Iterated Value Is: 3 > Iterated Value Is: 4 > Iterated Value Is: 5 > Iterated Value Is: 6 > Iterated Value Is: 7 > Iterated Value Is: 8 > Iterated Value Is: 9 > Iterated Value Is: 10 > Iterated Value Is: 11 > Iterated Value Is: 12 > > Now, I want to combine iterator with a slicing condition like > for i=list2 in list1: > print "Iterated Value Is:",i > > So, that I get the list in the slices like, > [1,2,3] > [4,5,6] > [7,8,9] > [10,11,12] > > But if I do this I get a Syntax Error, is there a solution? It'd be only polite if you actually included the traceback, instead of paraphrasing the error. > If anyone of the learned members may kindly let me know? > > Apology for any indentation error,etc. > > Thanking You in Advance, > > Regards, > Subhabrata > > > > let's examine the code that generates the syntax error. for i=list2 in list1: That doesn't match any of the grammar of Python, so it gives a syntax error. How could the compiler have interpreted it? Perhaps it could have thrown out the 'for' and the colon. That would be equivalent in this case to: i = False or we could toss out the "=list2" but that would give us your first loop. If I were doing this, I'd do something like (untested): temp = list1[:] #make a shallow copy of the list, so we're not modifying the original while temp print temp[:3] temp = temp[3:] I think you could do something similar with zip, but I don't have the energy this morning. -- DaveA -- http://mail.python.org/mailman/listinfo/python-list
Re: For Loop in List
On 01/13/13 06:45, subhabangal...@gmail.com wrote: Dear Group, I have a list like, list1=[1,2,3,4,5,6,7,8,9,10,11,12] Now, if I want to take a slice of it, I can. It may be done in, list2=list1[:3] print list2 [snip] Now, I want to combine iterator with a slicing condition like for i=list2 in list1: print "Iterated Value Is:",i So, that I get the list in the slices like, [1,2,3] [4,5,6] [7,8,9] [10,11,12] Well, you get a SyntaxError because, well, it's a syntax error. It may take a little math to do this: >>> SIZE = 3 >>> for i in range(len(list1)//SICE): ... print list1[i*SIZE:i*SIZE+SIZE] ... [1, 2, 3] [4, 5, 6] [7, 8, 9] [10, 11, 12] Or, you can exploit the fact that iterators exhaust inside a for-loop: >>> i = iter(list1) >>> for item in i: ... print [item, i.next(), i.next()] ... [1, 2, 3] [4, 5, 6] [7, 8, 9] [10, 11, 12] Hope this helps, -tkc -- http://mail.python.org/mailman/listinfo/python-list
Re: For Loop in List
2013/1/13 Tim Chase : > On 01/13/13 06:45, subhabangal...@gmail.com wrote: > SIZE = 3 for i in range(len(list1)//SICE): > ... print list1[i*SIZE:i*SIZE+SIZE] > ... > [1, 2, 3] > [4, 5, 6] > [7, 8, 9] > [10, 11, 12] > A little shorter and simpler version: >>> x = x[1:] >>> for i in range(0,len(x),SIZE): ... print x[i: i+SIZE] ... [1, 2, 3] [4, 5, 6] [7, 8, 9] [10, 11, 12] Hope it helps > Hope this helps, > > -tkc -- http://mail.python.org/mailman/listinfo/python-list
Re: problem with exam task for college
this is again a newer version, right now the velocity does in fact turn, but the view doesn't follow, it keeps the ship vertical. i'm also having trouble letting the flame appear when pressing the "up" button and when the ship rotates the horizontal velocity keeps getting bigger and bigger i also have to make the game end when the ship hits the moon on the wrong place i'm kinda stressed out because this has to be done by the 15th i've been studying like crazy the past week. If anyone could help me out i will deeply appreciate it, here is the code from visual import * import time import math import random from datetime import datetime import operator class lunar_lander(object): def __init__(self): scene.title = 'mini star wars' scene.width = 375 scene.height = 550 scene.center = (0,0) self.pos = (0,0) self.axis = 0 self.brandstofmeter = brandstofmeter() self.ruimteschip = ruimteschip() self.view = game_view(self) def play(self): t=0 dt=0.01 self.ruimteschip.updatemeter = False while t<9: time.sleep(0.01) self.ruimteschip.update(dt) t = t + dt if self.ruimteschip.updatemeter == True: self.brandstofmeter.update class game_view(object): def __init__(self,owner): autoscale=True box(pos=( 0, -375, 0), length=500, height=5, width=0, color = color.white) box(pos=(0,375, 0), length=500, height=5, width=0, color = color.white) box(pos=(-250,0, 0), length=5, height=750, width=0, color = color.white) box(pos=(250,0, 0), length=5, height=750, width=0, color = color.white) maan = curve(pos=[(-250,-353),(-240,-341),(-210,-354),(-199.5,-374)],color=color.red) maana = curve(pos=[(-199.5,-374),(-166,-374)],color=color.green) maanb = curve(pos=[(-166,-374),(-140,-357),(-80,-319),(-40,-361),(0,-321),(40,-329),(80,-347)],color=color.red) maanc = curve(pos=[(80,-347),(140,-347)],color=color.green) maand = curve(pos=[(140,-347),(162,-337),(189.5,-365),(210,-355),(240,-372),(250,-338)],color=color.red) for i in random.sample(range (-250,250),20): for j in random.sample(range (-375,375),20): sterren = points(pos = [i,j,0],size = 2, color=color.white) class brandstofmeter(object): def __init__(self): axis = 0 self.pos = (210,345) self.length = 25 self.height = 45 self.meter = box(pos = self.pos, length = self.length, height = self.height,color = color.green) def update(self): self.height = self.height - 0.2 print "ok" class ruimteschip(object): def __init__(self): self.pos = vector(0,330) self.acceleration = vector(0,-20,0) self.axis = (1,0,0) self.hoek = (90*math.pi)/180 self.graden = math.degrees(self.hoek) self.gas = vector(10 * cos(self.hoek),10 * sin (self.hoek)) self.velocity = vector(0,0,0) self.angle = pi / 2 self.updatemeter = False self.view = ruimteschip_view(self) self.vlam = self.view.vlam self.frame = self.view.frame self.zicht = brandstofmeter() def update(self,dt): self.velocity = self.velocity + (self.acceleration * dt) self.pos = self.pos + self.velocity * dt print self.velocity if scene.kb.keys: key = scene.kb.getkey() if key == "left": # linkerafwijking self.frame.axis -= (0, 0, 0.05) self.gas = vector(-sin(self.angle), cos(self.angle)) self.vlam.visible = True self.updatemeter = True elif key == "right": # rechterafwijking self.frame.axis += (0, 0, 0.05) self.gas = vector(sin(self.angle), cos(self.angle)) elif key == "up": self.velocity += self.gas self.frame.pos += self.velocity else: self.vlam.visible = False self.updatemeter = False self.velocity -= self.gas if self.pos.x > 250: self.pos.x = -250 if self.pos.x < -250: self.pos.x = 250 self.view.update(self) class ruimteschip_view(object): def __init__(self,owner): self.owner = owner self.frame = frame(pos = owner.pos,axis = owner.axis, velocity = owner.velocity) self.motor = curve(frame = self.frame,pos=[(0,24.0),(22.0,24.0),(22.0,39.0),(-22.0,39.0),(-22,24),(0,24)]) self.capsule = curve(frame = self.frame,color = color.blue ,pos=[(0,39),(-3,39),(-9,44),(-12,46),(-18,4
Re: For Loop in List
On 01/13/13 07:48, Boris FELD wrote: 2013/1/13 Tim Chase : SIZE = 3 for i in range(len(list1)//SICE): ... print list1[i*SIZE:i*SIZE+SIZE] A little shorter and simpler version: x = x[1:] for i in range(0,len(x),SIZE): ... print x[i: i+SIZE] Doh, I always forget that range() takes an optional stride. Or rather, I use it so infrequently that I reach for other alternatives before it occurs to me :) -tkc -- http://mail.python.org/mailman/listinfo/python-list
Re: ANN: Python training "text movies"
> That is right; I would also add that it may be overwhelming for a newbie > to be reading through a large "wall of text" -- here you have blank > space after the current paragraph so the attention is focused even more > on the last few lines. > > Additionally, since instructions scroll automatically, I can space them > out more than you would conventionally do in a manual. > Pretty cool. -- http://mail.python.org/mailman/listinfo/python-list
Creating continuous keystroke with python
I need to generate continuous keystroke with python. I have been trying with the sendkeys module, but the only command it supports is sending discrete keypresses. But I need a continous keypress, so that the other application (which in this case is a game which triggers an action only when a key is continously pressed for some time)can recognise it as such. Also I tried using the sendkeys function on pywin32 api, but it does the same thing too. My hope is there will be another function in pywin32 or some other api which can create seperate keydown event and keyup event so that I can bypass the keydown event for some time. -- http://mail.python.org/mailman/listinfo/python-list
Keyboard hook in linux
Hi! I am working on a small console app for linux. The idea is to display some sensor values and the screen should update itself in, say, every 10 seconds. The user should have the possibly to change some configurations or gwt help by pressing different keys (like you can do when running e.g. 'top'). In other words: the program should NOT wait for the keypress (so input() is not the solution), but simply capture keypresses and act accordingly. If no key is pressed, the program should continue updating the screen. Practically I am looking for something similar than Pascal's "keypressed" function (http://www.freepascal.org/docs-html/rtl/crt/keypressed.html). The python code would be something like this: --- snip --- while True: if keypressed: ch=screen.getch() # From 'curses' # Test, if 'ch' is a valid key # Do what the user want read_sensors() update_screen() --- snip --- I have searched in the Web and in several tutorials (e.g. "Programming python"), but this seems to be a tricky one. The 'pyHook' library seems to offer a keyboard hook manager, but 'pyHook' is not available for linux :( IMHO, the 'curses' library offers no (direct) solution to this... Does anybody have an idea / a solution, how to capture keystrokes in linux? Kind regards, Kimmo -- http://mail.python.org/mailman/listinfo/python-list
Re: Keyboard hook in linux
On 01/13/2013 09:13 AM, K. Elo wrote: > I am working on a small console app for linux. The idea is to display > some sensor values and the screen should update itself in, say, every 10 > seconds. > > The user should have the possibly to change some configurations or gwt > help by pressing different keys (like you can do when running e.g. > 'top'). In other words: the program should NOT wait for the keypress (so > input() is not the solution), but simply capture keypresses and act > accordingly. If no key is pressed, the program should continue updating > the screen. 'top' is built using a programming library called 'curses' or 'ncurses.' That's likely where you'll need to go to. At least if you want to be able to run properly on different terminals. ncurses handles terminal output including writing text at certain positions, and input/output, and even mouse interactions if you felt you needed that. It's apparently part of the standard python library: http://docs.python.org/2/library/curses.html -- http://mail.python.org/mailman/listinfo/python-list
Re: Keyboard hook in linux
On 01/13/2013 09:13 AM, K. Elo wrote: > I have searched in the Web and in several tutorials (e.g. "Programming > python"), but this seems to be a tricky one. The 'pyHook' library seems > to offer a keyboard hook manager, but 'pyHook' is not available for > linux :( IMHO, the 'curses' library offers no (direct) solution to this... You're wrong. curses does offer a direct solution to this. Check the docs. Also here's a nice intro document for Python 3: http://docs.python.org/dev/howto/curses.html You can check to see if a keystroke is waiting, grab it and then do something useful. curses can even grab keys like page up or page down. -- http://mail.python.org/mailman/listinfo/python-list
Re: problem with exam task for college
On 13 January 2013 13:57, wrote: > this is again a newer version, right now the velocity does in fact turn, but > the view doesn't follow, it keeps the ship vertical. > > i'm also having trouble letting the flame appear when pressing the "up" button > > and when the ship rotates the horizontal velocity keeps getting bigger and > bigger > > i also have to make the game end when the ship hits the moon on the wrong > place > > i'm kinda stressed out because this has to be done by the 15th i've been > studying like crazy the past week. If anyone could help me out i will deeply > appreciate it, here is the code > [SNIP] > > def update(self,dt): > self.velocity = self.velocity + (self.acceleration * dt) > self.pos = self.pos + self.velocity * dt > print self.velocity > > if scene.kb.keys: > key = scene.kb.getkey() > if key == "left": > # linkerafwijking > self.frame.axis -= (0, 0, 0.05) > self.gas = vector(-sin(self.angle), cos(self.angle)) > self.vlam.visible = True > self.updatemeter = True > > elif key == "right": > # rechterafwijking > self.frame.axis += (0, 0, 0.05) > self.gas = vector(sin(self.angle), cos(self.angle)) > > elif key == "up": > self.velocity += self.gas > self.frame.pos += self.velocity > else: > self.vlam.visible = False > self.updatemeter = False > self.velocity -= self.gas > > if self.pos.x > 250: > self.pos.x = -250 > if self.pos.x < -250: > self.pos.x = 250 > self.view.update(self) [SNIP] The function above is poorly organised. You should break this into several logical steps: 1) Process keypresses to update discrete state variables (such as whether or not the ship is thrusting. 2) Compute from the discrete state variables of the system what the acceleration will be, e.g.: acceleration = gravity if thrusting: acceleration += gas 3) Only once the acceleration is known apply the formulas to update the continuous state (position/velocity) of your system. If you rearrange it like this then you will probably be able to fix the logic bugs in the function above. In particular it is important that there should be only one place where you actually change each kind of state variable (velocity is modified in three places in the function above and I'm sure that this is related to the bugs you are having). Similar considerations apply to updating the angle of the ship. Also the update formula for the position is wrong. If I've understood your physics correctly, you should be using the equations of constant acceleration (my students know these as the "suvat" equations). In that case the formula should look like: newposition = oldposition + oldvelocity*dt + acceleration*dt**2 newvelocity = oldvelocity + acceleration*dt Your code is missing the quadratic term at the end of the first line above. (Actually the situation would be more complicated than this when the ship is also rotating but I don't understand exactly what your rotation physics is supposed to be). Oscar -- http://mail.python.org/mailman/listinfo/python-list
Re: For Loop in List
On 01/13/2013 07:45 AM, subhabangal...@gmail.com wrote: Dear Group, I have a list like, list1=[1,2,3,4,5,6,7,8,9,10,11,12] Now, if I want to take a slice of it, I can. It may be done in, list2=list1[:3] print list2 [1, 2, 3] If I want to iterate the list, I may do as, for i in list1: print "Iterated Value Is:",i Iterated Value Is: 1 Iterated Value Is: 2 Iterated Value Is: 3 Iterated Value Is: 4 Iterated Value Is: 5 Iterated Value Is: 6 Iterated Value Is: 7 Iterated Value Is: 8 Iterated Value Is: 9 Iterated Value Is: 10 Iterated Value Is: 11 Iterated Value Is: 12 Now, I want to combine iterator with a slicing condition like for i=list2 in list1: print "Iterated Value Is:",i So, that I get the list in the slices like, [1,2,3] [4,5,6] [7,8,9] [10,11,12] But if I do this I get a Syntax Error, is there a solution? If anyone of the learned members may kindly let me know? Apology for any indentation error,etc. Thanking You in Advance, Regards, Subhabrata Another good answer is to use a recipe from itertools docs page. There are a lot of good recipes there and you may want to keep them all in a module you can import from when needed. Here is the recipe: def grouper(n, iterable, fillvalue=None): """From itertools recipes: collect data into fixed-length chunks or blocks.""" # grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx args = [iter(iterable)] * n return zip_longest(fillvalue=fillvalue, *args) >>> list(grouper(3, range(12)) ... ... ... ... ) [(0, 1, 2), (3, 4, 5), (6, 7, 8), (9, 10, 11)] HTH, - mitya -- Lark's Tongue Guide to Python: http://lightbird.net/larks/ -- http://mail.python.org/mailman/listinfo/python-list
Re: pylint or similar to test version-specific language constructs?
Hi Dave On 11 Jan, 15:06, Dave Angel wrote: > > Not sure what you mean by beforehand. Don't you run all your unit tests > before putting each revision of your code into production? So run those > tests twice, once on 2.7, and once on 2.4. A unit test that's testing > code with a ternary operator will fail, without any need for a separate > test. > > if it doesn't, then you've got some coverage gaps in your unit tests. By 'beforehand' I meant 'before testing on my target 2.4 system; perhaps I should have been clearer in that I am running 2.7 on my 'development' platform, and 2.4 on my target. It would be painful to put 2.4 on my target system (although I continue to wonder about that...). So I was looking to catch such errors before migrating to the target. [Steven D'Aprano] > Decorators work fine in Python 2.4. Yes, I was just coming up with another example of a language construct which didn't exist at one point. > You don't even need tests for the code that includes the ternary > operator. The module simply won't compile in Python 2.4, you get a > SyntaxError when you try to import it or run it. In fact I had a misapprehension about this; for some reason (I thought I'd tried it) I thought such an error only got caught at runtime, not 'compile-time'. I now see that this is not the case, which means the athe problem is less of a concern than I thought. Thanks for the comments. Jon N -- http://mail.python.org/mailman/listinfo/python-list
Upgrading Python with NumPy, SciPy and Mayavi in a Rocks 6.0 cluster
Hi, We are looking for some guidance in installing an upgraded Python on our cluster. Our cluster was installed with Rocks 6.0, is running CentOs 6.2, and has python-2.6.6, gcc-4.4.6. We would like to install an upgraded version of Python along with the following modules NumPy Scipy (which will require a compatible version of the Atlas libraries) Mayavi (which will require a compatible version of vtk) We were wondering if anyone has experience in installing these packages, what are the best combinations of compatible versions, what other upgrades will be needed (e.g. will we need to upgrade the gnu compilers to install the latest versions) and where these should be installed (local disks, /share/apps, other?). A little more background, our students are currently working with a local installation using Python-2.7.1 numpy-1.5.1 scipy-0.9.0b1 Mayavi-3.4.0 ATLAS-3.8.3 vtk-5.4 We would like to install these packages in a more appropriate, cluster-wide area and upgrade these packages as appropriate. We are also aware of a Rocks python roll which contains python-2.7.2 and an upspecified version of NumPy (is it possible to find out which version, before installing the roll?). Thanks -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Pat Haley Email: pha...@mit.edu Center for Ocean Engineering Phone:(617) 253-6824 Dept. of Mechanical Engineering Fax:(617) 253-8125 MIT, Room 5-213 http://web.mit.edu/phaley/www/ 77 Massachusetts Avenue Cambridge, MA 02139-4301 -- http://mail.python.org/mailman/listinfo/python-list
Re: Keyboard hook in linux
K. Elo wrote:
> Practically I am looking for something similar than Pascal's
> "keypressed" function
As already mentioned, (n)curses is a good solution.
However, if you need/want to go to lower levels, you can read
/dev/input/event* like this (excerpt from one of my programs):
def opendevs():
return [os.open(dev, os.O_RDONLY) for dev in glob.glob("/dev/input/event*")]
def readevent(fds):
try:
# file descriptor has disappeared - we unplugged the keyboard,
# resumed from suspend etc...
ps = [os.read(fd, 16) for fd in fds]
except OSError:
traceback.print_exc()
yield None, None, None
for p in ps:
timeval, suseconds, typ, code, value = struct.unpack( 'llHHI', p[:16])
yield typ, value, code
def run_print(fds):
while 1:
rs, ws, xs = select.select(fds, [], [])
for t, v, e in readevent(rs):
print "Event code:", e, "type:", t, "value:", v
fds = opendevs()
run_print(fds)
This is of course not portable at all (and won't run on ancient
Linuces), but the advantage is that you can hook to the keys or key
combinations curses cannot (e.g. modifiers, Scrolllock etc...) and the
program can react to the key events even in the background.
--
---
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| __..--^^^--..__garabik @ kassiopeia.juls.savba.sk |
---
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http://mail.python.org/mailman/listinfo/python-list
Re: Keyboard hook in linux
Hi! Thanks, Michael, for your quick - and heplful - reply. 13.01.2013 18:46, Michael Torrie wrote: You're wrong. curses does offer a direct solution to this. Check the docs. Also here's a nice intro document for Python 3: http://docs.python.org/dev/howto/curses.html You are right :) The docs tell us (I somehow missed this when reading the doc last time): "It’s possible to change this behavior with the method nodelay(). After nodelay(1), getch() for the window becomes non-blocking and returns curses.ERR (a value of -1) when no input is ready. There’s also a halfdelay() function, which can be used to (in effect) set a timer on each getch(); if no input becomes available within a specified delay (measured in tenths of a second), curses raises an exception." This is actually funny: if you google for e.g. "capture keystrokes python", you will find masses of suggestions, none of them having this simple and elegant (i.e. python-like :) ) solution included. Now it works and my problem is solved. Thank you! Kind regards, Kimmo -- http://mail.python.org/mailman/listinfo/python-list
Subgraph Drawing
Dear Group, I have two questions, if I take a subseries of the matrix as in eigenvalue here, provided I have one graph of the full form in G, how may I show it, as if I do the nx.draw(G) it takes only the original graph. >>> import numpy >>> import networkx as nx >>> import matplotlib.pyplot as plt >>> G=nx.Graph() >>> G.add_edges_from([(1,2),(1,3),(1,3),(1,4),(1,5),(1,6),(1,7),(1,8)]) >>> L =nx.laplacian(G) >>> print L [[ 7. -1. -1. -1. -1. -1. -1. -1.] [-1. 1. 0. 0. 0. 0. 0. 0.] [-1. 0. 1. 0. 0. 0. 0. 0.] [-1. 0. 0. 1. 0. 0. 0. 0.] [-1. 0. 0. 0. 1. 0. 0. 0.] [-1. 0. 0. 0. 0. 1. 0. 0.] [-1. 0. 0. 0. 0. 0. 1. 0.] [-1. 0. 0. 0. 0. 0. 0. 1.]] >>> print numpy.linalg.eigvals(L) [ 8.e+00 2.22044605e-16 1.e+00 1.e+00 1.e+00 1.e+00 1.e+00 1.e+00] for more than 1000 nodes it is coming too slow on Windows 7 machine with 3GB RAM. If any one of the learned members can help. Apology for any indentation error etc. Thanking all in Advance, Regards, Subhabrata Banerjee. -- http://mail.python.org/mailman/listinfo/python-list
please solve my problem
hello i need help for my ecommerce project ,and here i am facing some problem
here is my
query
"i want to show image by the help of MEDIA_URL and this is my template file
code for this
http://en.wikipedia.org/wiki/List_of_tz_zones_by_name
# although not all choices may be available on all operating systems.
# In a Windows environment this must be set to your system time zone.
TIME_ZONE = 'America/Chicago'
# Language code for this installation. All choices can be found here:
# http://www.i18nguy.com/unicode/language-identifiers.html
LANGUAGE_CODE = 'en-us'
SITE_ID = 1
# If you set this to False, Django will make some optimizations so as not
# to load the internationalization machinery.
USE_I18N = True
# If you set this to False, Django will not format dates, numbers and
# calendars according to the current locale.
USE_L10N = True
# If you set this to False, Django will not use timezone-aware datetimes.
USE_TZ = True
# Absolute filesystem path to the directory that will hold user-uploaded files.
# Example: "/home/media/media.lawrence.com/media/"
#MEDIA_ROOT = "C:/Users/rakesh/Desktop/ecomstore/static/"
MEDIA_ROOT = ''
# URL that handles the media served from MEDIA_ROOT. Make sure to use a
# trailing slash.
# Examples: "http://media.lawrence.com/media/";, "http://example.com/media/";
MEDIA_URL = '/static/'
#MEDIA_URL = "http://localhost:8000/static/";
# Absolute path to the directory static files should be collected to.
# Don't put anything in this directory yourself; store your static files
# in apps' "static/" subdirectories and in STATICFILES_DIRS.
# Example: "/home/media/media.lawrence.com/static/"
STATIC_ROOT = ''
# URL prefix for static files.
# Example: "http://media.lawrence.com/static/";
STATIC_URL = '/static/'
# Additional locations of static files
STATICFILES_DIRS = (
#"C:Users/rakesh/Desktop/ecomstore/static/"
# Put strings here, like "/home/html/static" or "C:/www/django/static".
# Always use forward slashes, even on Windows.
# Don't forget to use absolute paths, not relative paths.
)
# List of finder classes that know how to find static files in
# various locations.
STATICFILES_FINDERS = (
'django.contrib.staticfiles.finders.FileSystemFinder',
'django.contrib.staticfiles.finders.AppDirectoriesFinder',
#'django.contrib.staticfiles.finders.DefaultStorageFinder',
)
# Make this unique, and don't share it with anybody.
SECRET_KEY = '2h(8t+9z4z-m(fuhl17eqp78q!yxo4&i54jofml3uoyv@a3y3x'
# List of callables that know how to import templates from various sources.
TEMPLATE_LOADERS = (
'django.template.loaders.filesystem.Loader',
'django.template.loaders.app_directories.Loader',
# 'django.template.loaders.eggs.Loader',
)
MIDDLEWARE_CLASSES = (
'django.middleware.common.CommonMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
#'djangodblog.DBLogMiddleware',
# Uncomment the next line for simple clickjacking protection:
# 'django.middleware.clickjacking.XFrameOptionsMiddleware',
)
ROOT_URLCONF = 'ecomstore.urls'
# Python dotted path to the WSGI application used by Django's runserver.
WSGI_APPLICATION = 'ecomstore.wsgi.application'
TEMPLATE_DIRS = (
os.path.join(CURRENT_PATH,'templates'),
"C:/Users/rakesh/Desktop/ecomstore/templates/",
#"C:/Python27/Lib/site-packages/django/contrib/admin/templates/admin",
# Put strings here, like "/home/html/django_templates" or
"C:/www/django/templates".
# Always use forward slashes, even on Windows.
# Don't forget to use absolute paths, not relative paths.
)
INSTALLED_APPS = (
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.staticfiles',
'catalog',
#'djangodblog',
# Uncomment the next line to enable the admin:
'django.contrib.admin',
# Uncomment the next line to enable admin documentation:
'django.contrib.admindocs',
'preview',
'utils',
)
# A sample logging configuration. The only tangible logging
# performed by this configuration is to send an email to
# the site admins on every HTTP 500 error when DEBUG=False.
# See http://docs.djangoproject.com/en/dev/topics/logging for
# more details on how to customize your logging configuration.
LOGGING = {
'version': 1,
'disable_existing_loggers': False,
'filters': {
'require_debug_false': {
'()': 'django.utils.log.RequireDebugFalse'
}
},
'handlers': {
'mail_admins': {
'level': 'ERROR',
'filters': ['require_debug_false'],
'class': 'django.utils.log.AdminEmailHandler'
}
},
'loggers': {
'django.request': {
'handlers': ['mail
Re: please solve my problem
In article <72e8aec3-4fa3-44af-aad7-8b32196da...@googlegroups.com>, Divya Thakur wrote: > "i want to show image by the help of MEDIA_URL and this is my template file > code for this > not working This is a django-specific question. You would do better to ask on the django-users mailing list: https://groups.google.com/forum/?fromgroups#!forum/django-users -- http://mail.python.org/mailman/listinfo/python-list
Re: please solve my problem
On Mon, Jan 14, 2013 at 7:35 AM, Divya Thakur wrote: > raise TemplateDoesNotExist(name) > TemplateDoesNotExist: 500.html > [14/Jan/2013 01:08:11] "GET /static/images/products/thumbnails/12345 > HTTP/1.1" 500 59 This sounds like a Django-specific issue. You'll probably get better results from a more Django-specific list: https://www.djangoproject.com/community/ > here is my settings.py file > # Make this unique, and don't share it with anybody. > SECRET_KEY = '2h(8t+9z4z-m(fuhl17eqp78q!yxo4&i54jofml3uoyv@a3y3x' You've just dumped a huge amount of text to us, including something that probably shouldn't have been shared. I strongly recommend you change this key, now that it's gone public, and consider trimming your text down to just what's needed to reproduce the problem. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: pylint or similar to test version-specific language constructs?
On Mon, Jan 14, 2013 at 4:56 AM, jkn wrote: > Hi Dave > > On 11 Jan, 15:06, Dave Angel wrote: >> >> Not sure what you mean by beforehand. Don't you run all your unit tests >> before putting each revision of your code into production? So run those >> tests twice, once on 2.7, and once on 2.4. A unit test that's testing >> code with a ternary operator will fail, without any need for a separate >> test. >> >> if it doesn't, then you've got some coverage gaps in your unit tests. > > By 'beforehand' I meant 'before testing on my target 2.4 system; > perhaps I should have been clearer in that I am running 2.7 on my > 'development' platform, and 2.4 on my target. It would be painful to > put 2.4 on my target system (although I continue to wonder about > that...). So I was looking to catch such errors before migrating to > the target. Painful to put 2.4 on your dev, you mean? I've never done it, but I would expect that the old sources will compile against newer libraries with no problems. That's likely to be the easiest option. It's the language-level equivalent of watching for a thrown exception rather than asking forgiveness beforehand :) ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: please i need explanation
On Sun, 13 Jan 2013 15:04:34 -0600, Tony the Tiger wrote: > On Fri, 11 Jan 2013 09:35:10 -0600, kwakukwatiah wrote: > >> >> >> >> >> def factorial(n): > > Right, another html junkie, on windoze, no doubt. X-Mailer: Microsoft Windows Live Mail 15.4.3508.1109 -- http://mail.python.org/mailman/listinfo/python-list
Re: Subgraph Drawing
On 13 January 2013 20:05, wrote: > Dear Group, > > I have two questions, if I take a subseries of the matrix as in eigenvalue > here, > provided I have one graph of the full form in G, how may I show it, as if I > do the nx.draw(G) it takes only the original graph. I'm sorry, but I really don't understand what you mean. When you say "subseries" do you mean "subgraph"? Or do you mean a subset of the eigenvalues? It would be good if you could give a simple example of what you mean using code and showing the expected/desired output. > import numpy import networkx as nx import matplotlib.pyplot as plt G=nx.Graph() G.add_edges_from([(1,2),(1,3),(1,3),(1,4),(1,5),(1,6),(1,7),(1,8)]) L =nx.laplacian(G) print L > [[ 7. -1. -1. -1. -1. -1. -1. -1.] > [-1. 1. 0. 0. 0. 0. 0. 0.] > [-1. 0. 1. 0. 0. 0. 0. 0.] > [-1. 0. 0. 1. 0. 0. 0. 0.] > [-1. 0. 0. 0. 1. 0. 0. 0.] > [-1. 0. 0. 0. 0. 1. 0. 0.] > [-1. 0. 0. 0. 0. 0. 1. 0.] > [-1. 0. 0. 0. 0. 0. 0. 1.]] print numpy.linalg.eigvals(L) > [ 8.e+00 2.22044605e-16 1.e+00 1.e+00 >1.e+00 1.e+00 1.e+00 1.e+00] > > for more than 1000 nodes it is coming too slow on Windows 7 machine with 3GB > RAM. What is too slow? Oscar -- http://mail.python.org/mailman/listinfo/python-list
Re: Subgraph Drawing
On Sun, 13 Jan 2013 12:05:54 -0800, subhabangalore wrote: > Dear Group, > > I have two questions, if I take a subseries of the matrix as in > eigenvalue here, provided I have one graph of the full form in G, how > may I show it, as if I do the nx.draw(G) it takes only the original > graph. Is this what you mean? If not, you will have to explain your question better. L = = nx.laplacian(G) E = numpy.linalg.eigvals(L) nx.draw(E) > >>> print numpy.linalg.eigvals(L) > [ 8.e+00 2.22044605e-16 1.e+00 1.e+00 >1.e+00 1.e+00 1.e+00 1.e+00] > for more than 1000 nodes it is coming too slow on Windows 7 machine with > 3GB RAM. Get a faster machine. Or use fewer nodes. Or be patient and wait. Solving a graph problem with 1000 nodes is a fairly big problem for a desktop PC. It will take time. Calculations don't just happen instantly, the more work you have to do the longer they take. The last alternative is to ask on a specialist numpy list. But I expect they will probably tell you the same thing. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Beowulf clusters
On Sun, Jan 13, 2013 at 8:19 PM, Oscar Benjamin wrote: > On 14 January 2013 02:10, Mark Janssen wrote: >> Has anyone used python for high-performance computing on Beowulf clusters? > > Yes. How did they deal with the Global interpreter lock across many machines? Cheers, Mark -- http://mail.python.org/mailman/listinfo/python-list
Re: Beowulf clusters
On 14 January 2013 02:22, Mark Janssen wrote: > On Sun, Jan 13, 2013 at 8:19 PM, Oscar Benjamin > wrote: >> On 14 January 2013 02:10, Mark Janssen wrote: >>> Has anyone used python for high-performance computing on Beowulf clusters? >> >> Yes. > > How did they deal with the Global interpreter lock across many machines? Unless I've drastically misunderstood something there is no GIL across many machines. The GIL is a per-process lock so there is a different GIL for each process on the same machine and there is no interaction between the GILs on the same, or on different, machines. Oscar -- http://mail.python.org/mailman/listinfo/python-list
Re: Beowulf clusters
On 14 January 2013 02:46, Mark Janssen wrote: > On Sun, Jan 13, 2013 at 8:37 PM, Oscar Benjamin > wrote: >> On 14 January 2013 02:33, Mark Janssen wrote: >>> Lol, well that's why I'm asking. I don't see how they can do it >>> without considerable difficulties. >> >> What do you want the GIL for across machines? The normal purpose of >> the GIL is to preserve the integrity of Python's in-memory data >> structures. These are only accessible within one process so what good >> would a multi-process GIL be? > > Excuse me, I actually thought you knew what you were talking about. Steady on... > A Beowulf cluster, by it's nature, is across many-machines. Now you > can't have a GIL and a single python program across many-machines > without some tricks. I'm just wondering how (or if) they solved that > problem You've used the word 'program'. I used the word 'process'. I have used HPC clusters that I assume count as Beowulf clusters. However, I have never used them in such a way that a single process occurred on multiple machines (the idea seems absurd to me). Maybe I've missed something here... Oscar -- http://mail.python.org/mailman/listinfo/python-list
Re: Beowulf clusters
On Sun, Jan 13, 2013 at 8:37 PM, Oscar Benjamin wrote: > On 14 January 2013 02:33, Mark Janssen wrote: >> Lol, well that's why I'm asking. I don't see how they can do it >> without considerable difficulties. > > What do you want the GIL for across machines? The normal purpose of > the GIL is to preserve the integrity of Python's in-memory data > structures. These are only accessible within one process so what good > would a multi-process GIL be? Excuse me, I actually thought you knew what you were talking about. A Beowulf cluster, by it's nature, is across many-machines. Now you can't have a GIL and a single python program across many-machines without some tricks. I'm just wondering how (or if) they solved that problem mark -- http://mail.python.org/mailman/listinfo/python-list
Re: Beowulf clusters
When you write HPC code the GIL isn't an issue, but you'll have plenty of others. Craig reporting from the road 10550 N Torrey Pines Rd La Jolla CA 92037 work: 858 784 9208 cell: 619 623 2233 On Jan 13, 2013, at 6:22 PM, Mark Janssen wrote: > On Sun, Jan 13, 2013 at 8:19 PM, Oscar Benjamin > wrote: >> On 14 January 2013 02:10, Mark Janssen wrote: >>> Has anyone used python for high-performance computing on Beowulf clusters? >> >> Yes. > > How did they deal with the Global interpreter lock across many machines? > > Cheers, > > Mark > -- > http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: Subgraph Drawing
On Monday, January 14, 2013 6:05:49 AM UTC+5:30, Steven D'Aprano wrote: > On Sun, 13 Jan 2013 12:05:54 -0800, subhabangalore wrote: > > > > > Dear Group, > > > > > > I have two questions, if I take a subseries of the matrix as in > > > eigenvalue here, provided I have one graph of the full form in G, how > > > may I show it, as if I do the nx.draw(G) it takes only the original > > > graph. > > > > Is this what you mean? If not, you will have to explain your question > > better. > > > > > > L = = nx.laplacian(G) > > E = numpy.linalg.eigvals(L) > > nx.draw(E) > > > > > > > >>> print numpy.linalg.eigvals(L) > > > [ 8.e+00 2.22044605e-16 1.e+00 1.e+00 > > >1.e+00 1.e+00 1.e+00 1.e+00] > > > for more than 1000 nodes it is coming too slow on Windows 7 machine with > > > 3GB RAM. > > > > Get a faster machine. Or use fewer nodes. Or be patient and wait. > > > > Solving a graph problem with 1000 nodes is a fairly big problem for a > > desktop PC. It will take time. Calculations don't just happen instantly, > > the more work you have to do the longer they take. > > > > The last alternative is to ask on a specialist numpy list. But I expect > > they will probably tell you the same thing. > > > > > > -- > > Steven Dear Steven, Thank you for your kind effort. You got the problem right. But it is giving following error, Traceback (most recent call last): File "", line 1, in nx.draw(E) File "C:\Python27\lib\site-packages\networkx\drawing\nx_pylab.py", line 138, in draw draw_networkx(G,pos=pos,ax=ax,**kwds) File "C:\Python27\lib\site-packages\networkx\drawing\nx_pylab.py", line 267, in draw_networkx pos=nx.drawing.spring_layout(G) # default to spring layout File "C:\Python27\lib\site-packages\networkx\drawing\layout.py", line 241, in fruchterman_reingold_layout A=nx.to_numpy_matrix(G,weight=weight) File "C:\Python27\lib\site-packages\networkx\convert.py", line 492, in to_numpy_matrix nodelist = G.nodes() AttributeError: 'numpy.ndarray' object has no attribute 'nodes' >>> there are other solution of converting back the matrix to graph should I try that? Regards, Subhabrata. -- http://mail.python.org/mailman/listinfo/python-list
Re: Subgraph Drawing
On Sun, 13 Jan 2013 20:01:21 -0800, subhabangalore wrote: > there are other solution of converting back the matrix to graph should I > try that? Yes. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: PyWart: Module access syntax
On Saturday, January 12, 2013 12:45:03 AM UTC-6, Steven D'Aprano wrote:
> On Fri, 11 Jan 2013 20:34:20 -0800, Rick Johnson wrote:
> > [...]
> So what do you do for, say, os.path? According to the first rule, you
> must write it as os:path because path is a module; according to the
> second rule, you must write it as os.path because path is a member of os.
> So which rule wins?
Since "path" is an identifier in the module "os" that points to a system
specific module (which is loaded at run-time), you would access os.path just as
you do today; using the dot. No changes here. Next!
> If I do this:
>
> import math
> import string
> math.string = string
>
> is that legal, or do I have to write "math:string = string"?
No. You are assigning the module "string" to a member variable of the module
"math" so you use the dot. No changes here. Next!
> Suppose I do this:
*rolls-eyes*
> import random
> if random.random() < 0.5:
> math.string = "NOBODY expects the Spanish Inquisition!"
> else:
> math.string = string # assuming this actually is allowed
...first allow me to remove all the cruft so you can ask this next iteration of
the _same_ hypothetical question succinctly.
if some_condition:
math.string = ""
else
math.string = string
> How do I access the string member?
You access the member variable named "string" (that points to the "string
module") as you would ANY _member_, using the dot. Next!
> try:
> print math.string # only works if string is a str object
> except SomeException:
> print math:string # only works if string is a module object
EARTH TO STEVEN: You are sadly misunderstanding my suggested syntax and frankly
making a complete fool of yourself. I cannot allow this to go on any longer.
> That would suck *and* blow at the same time.
Yes it would, but that's only _IF_ my suggested syntax works in the backwards
way you suggest. Lucky for us, i'm designing this feature.
> I don't need to know the
> type of any other member object in order to look it up, why should I have
> to care whether it is a module?
I said it before and i'll say it again: If you don't know if your calls are
accessing module space or object space (be it instanced object or static
object), then you are sadly informed and shooting from the hip -- you're going
to shoot your toes off! But that is not the worst part, no. The worst part is
that by using only the dot, your code is superfluously obfuscated. That is a
crime to me. A crime punishable by the syntax error. I condemn you to tortuous
syntax errors until you change your rebellious ways.
> Now, suppose I then do this:
>
> class Blob: pass
>
> blob = Blob()
> blob.math = math # or should that be blob:math ?
Oh lord.
Has anyone noticed that every one of these hypotheticals is presenting the very
same question using different circumstances. Do you think 1+1 will sometimes
equal 2 Steven?
You are missing the point of this syntax. The colon is to access MODULE
NAMESPACE. The dot is to access MODULE MEMBERS. A module CAN BE another
module's MEMBER.
You are also unable to grasp this simple logical fact: Once you arrive at /any/
MODULE and you start accessing MEMBERS, you will *_ALWAYS_* find members from
that point downwards.
Observe:
In module "lib:foo":
import string
import math
import math as _math
from math import ceil
#
string.math = math
string.math.var="var"
In __main__ (test 1):
import lib:foo
import lib:foo as foo
# Test 1
print lib:foo.string.math.var -> "var"
# Test 2
print foo.string.math.var -> "var"
# Test 3
foo.string.math.ceil(.1) -> 1.0
# Test 4:
foo.ceil(.1) -> 1.0
> [...]
>
> > Traceback (most recent call last):
> > File "", line 1, in
> > dlg = lib:gui:tkinter:dialogs.simpledialog()
>
>
> Of course it is an object. *Everything* in Python is an object.
And i agree! ("it" being "modules" in this case)
> Modules
> are objects. Strings are objects. Types and classes are objects.
Wait, "classes" are NOT objects. Classes are structured code that DEFINE an
object. You see, this is exactly why we need to stop using the word "class" to
describe an "object definition". Your ability to grasp _what_ an object
definition *IS* is due to poor terminology.
> None is
> an object. Metaclasses are objects. Properties are objects. Exceptions
> are objects. Have I made it clear yet?
Yes, but your point is invalid. I was comparing a module to an object. And even
though EVERYTHING in Python is technically an object, you should have inferred
the meaning of my comparison, but alas, you cannot even infer my syntax!
> > *The problem:*
> > ... is readability. The current dot syntax used ubiquitously in paths is
> > not conveying the proper information to the reader, and in-fact
> > obfuscating the code.
>
> So you say. I think you are caring too much about the type of members and
> not enough about what interface th
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Re: ANN: Python training "text movies"
In article , Jason Friedman wrote: > > That is right; I would also add that it may be overwhelming for a newbie > > to be reading through a large "wall of text" -- here you have blank > > space after the current paragraph so the attention is focused even more > > on the last few lines. > > > > Additionally, since instructions scroll automatically, I can space them > > out more than you would conventionally do in a manual. > > > > Pretty cool. When reading the source of the Web page which shows the scroll, I can't find the reference to the text displayed. Only "text"... How may we use the software which generates the Javascript ? Thanks, it's cool. franck -- http://mail.python.org/mailman/listinfo/python-list
PyWart (Terminolgy): "Class"
I have believed for a very long time that "class" was a poor choice of keyword to designate an "object definition". Firstly, the word /class/ does not transform smoothly into CS from English. NO English definition of "class" comes anywhere close to describing the "structured source code that defines an object". Or even generally as: "something that defines something else". You could try to hammer "classification" into the round hole, but you soon find out it's just a damn square peg! Secondly, "class" is confusing to newbies. How can someone understand the fundamentals of OOP (which defines objects and interfaces) when they are asked to write classes? (teacher:) "Okay /class/, we are going to create a new object by writing a class." (student:) HUH? Thirdly, once people *DO* understand that a "class" is simply an "object definition", they still go on to say idiotic things like: "Classes are objects"! It is obvious these people are a victim of their own terminology. Other possible terms include: "subclass": Since every "user defined object" *must* subclass /something/, using this word would infer such a relationship to the reader. HOWEVER, we would then need to differentiate the general usage of "subclass" (as in: an object that is an extension of another object) from a "user defined subclass" (as in: source code). In any event, "subclass" is a good contender. He's going to the 12th round for sure. "template": This term is very close, but still lacking a concrete relationship between source code (definition of object) and the resulting "thing" living in memory (object). I think this one is TKO in round 3. "object": This is my favorite word however it does suffer a "verbial" disconnection. What are we suggesting? A single word can be very ambiguous as to intent. However, if we couple the word "object" with the word "define" we then inject intent. "define object" on it's face is perfect! We know everything we need to know. 1) We are defining "something" and 2) that *THAT* "something" is an object! YAY! Now since "methods" and "functions" (PyWart on these terms coming soon!) require defining, the syntax will now be symmetrical (omitting for now that funcs/meths only use "def"!). However we could drop the "def" and use only "object" to save a few keystrokes and a lot of pyparsing. I am sure the main arguments against such a clear and logical syntax would be that we would confuse "object definitions" with "real live objects" in normal conversation. But i say that is non-sense because we NEED to be more specific when conversing anyway. Choosing a word like "class" just because we don't want to use two words to refer to "source code that defines an object" (in conversation) is ridiculous. This syntax will inject specificity into our communications and convey meaning more appropriately. Dear language designers: Stop propagating such foolish terminology! End the infection of "class" in all source code, docs, and daily conversation. Be more consistent and logical. Resist temptation to use poor terminology simply because other languages have done so before you. Grow a pair already! -- http://mail.python.org/mailman/listinfo/python-list
Re: ANN: Python training "text movies"
On 01/14/2013 01:34 AM, Franck Ditter wrote: In article , Jason Friedman wrote: That is right; I would also add that it may be overwhelming for a newbie to be reading through a large "wall of text" -- here you have blank space after the current paragraph so the attention is focused even more on the last few lines. Additionally, since instructions scroll automatically, I can space them out more than you would conventionally do in a manual. Pretty cool. When reading the source of the Web page which shows the scroll, I can't find the reference to the text displayed. Only "text"... How may we use the software which generates the Javascript ? Thanks, it's cool. franck Thanks! the text is in var commands = ... You can download the generator script here: https://github.com/pythonbyexample/PBE/blob/master/code/jstmovie.py (you also need to grab tmovies dir) -- Lark's Tongue Guide to Python: http://lightbird.net/larks/ -- http://mail.python.org/mailman/listinfo/python-list
Re: PyWart (Terminolgy): "Class"
On Mon, Jan 14, 2013 at 5:46 PM, Rick Johnson wrote: > Dear language designers: Stop propagating such foolish terminology! End the > infection of "class" in all source code, docs, and daily conversation. Be > more consistent and logical. Resist temptation to use poor terminology simply > because other languages have done so before you. Grow a pair already! Absolutely. We should learn from Lars Pensjö and start referring to "blueprint objects" and "clones". Or take the updated version and call them "programs" and "objects". I'm sure that'll make a huge amount more sense than using the terms that millions of programmers already understand. Alternatively, we could take the Humpty Dumpty approach and assign meanings to names arbitrarily. But wait till Saturday night when they come for their wages. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: PyWart (Terminolgy): "Class"
On Monday 1-14-2013 at 12:46 AM, Rick Johnson wrote:
> [...]
> "object":
>
> This is my favorite word however it does suffer a
> "verbial" disconnection. What are we suggesting? A single
> word can be very ambiguous as to intent. However, if we
> couple the word "object" with the word "define" we then
> inject intent. "define object" on it's face is perfect!
I just had an epiphany of sorts.
I really don't like using two words ("define object", or "def obj") and using
one single keyword is ambiguous ("object" or "obj"). So the obvious solution is
to combine the abbreviated words into one compound keyword that will save
keystrokes, save parsing, and all-the-while maintain symmetry. That keyword is
"defobj". Coupled with "defmeth" and "deffunc" we now have a symmetrical
definition syntax!
deffunc bar():
return
defobj Foo():
defmeth __init__(self, blah):
pass
Extra Credit: Can anyone think of a better solution for defining objects
without using keywords at all? Hmm... I'm getting a chubby just thinking about
it!
--
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Re: PyWart (Terminolgy): "Class"
On Mon, Jan 14, 2013 at 6:32 PM, Rick Johnson
wrote:
> I really don't like using two words ("define object", or "def obj") and using
> one single keyword is ambiguous ("object" or "obj"). So the obvious solution
> is to combine the abbreviated words into one compound keyword that will save
> keystrokes, save parsing, and all-the-while maintain symmetry. That keyword
> is "defobj". Coupled with "defmeth" and "deffunc" we now have a symmetrical
> definition syntax!
>
> deffunc bar():
>return
>
> defobj Foo():
> defmeth __init__(self, blah):
> pass
Awesome! Now, just one more step to make Python into the World's Most
Awesome Language(tm): Replace those lengthy words with single symbols
found in the Unicode set; compress everything down and enforce perfect
Unicode handling. Also, demand that names be one character long, to
enforce creativity by the Mark Rosewater principle. We will then have
a truly wonderful language; everything will be so utterly readable.
ChrisA
--
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