Re: using PIL for PCA analysis

>Paul McGuire wrote > # following approx fromhttp://www.dfanning.com/ip_tips/color2gray.html > grayscale = lambda (R,G,B) : int(0.3*R + 0.59*G + 0.11*B) > print [ [ grayscale(rgb) for rgb in row ] for row in sampledata ] Paul in PIL handbook ,they mention a Luma transform on page15, under the im

how to create eigenface image

hi all I am new to python and learning PCA method by reading up Turk&Petland papers etc while trying out PCA on a set of greyscale images using python, and numpy I tried to create eigenvectors and facespace. i have facesarray--- an NXP numpy.ndarray that contains data of images N=numof ima

Re: finding euclidean distance,better code?

> The code is pretty legible as it is now. Anyway, using min() and a > generator: > > hi is this calculated distance really Euclidean distance? When i checked wikipedia http://en.wikipedia.org/wiki/Euclidean_distance it shows a calculation involving sum of squares of the differences of elements.He

Re: finding euclidean distance,better code?

> the norm from which it is derived is called norm-1, or L1; the usual > > euclidean distance is derived from norm-2. > If you only want to see if two things are "close enough", this provides a > faster measure than the euclidean distance. thanks Gabriel for the detailed explanation.. if i w

how to list all installed modules

hi Is there a way to list all the installed modules in my python installation.I recently installed pygame and when i tried to import it like >>import pygame it complained that no such module was found.I can see the pygame directory in F:\Python25\Lib\site-packages in my machine,but am unable to imp

Re: how to list all installed modules

On Feb 18, 9:42 pm, Peter Otten <__pete...@web.de> wrote: > >>> help("modules") thanks Peter.That helped. > Regarding the original problem, do you have multiple Python installations? > If so, you may accidentally be running the "wrong" python. I have only one installation.It shows all other modul

Re: how to list all installed modules

On Feb 18, 11:10 pm, Scott David Daniels > Are you running F:\Python25\python.exe (or F:\Python25\pythonw.exe)? > open a command window (run cmd), and type: >      C:\> python >      ... >      >>> import sys >      >>> for dirname in  sys.path: >              print sys.path > > I suspect somethin

ImageTk.Photoimage not displayed

hi i am trying to display an image on a canvas in a gui made with Tkinter widgets class PhotoDisplay: def __init__(self,parent): self.mainframe = Frame(parent,background="grey") . #added a subframe to hold canvas and button self.canvFrame=Frame(

class definition syntax

hi i have seen some class definitions like class MyClass(object): def __init__(self): what does the object keyword inside the braces in MyClass() mean? Has it got any significance? thanks in advance harry -- http://mail.python.org/mailman/listinfo/python-list

use of super

hi I was going thru the weblog appln in practical django book by bennet .I came across this class Entry(Model): def save(self): dosomething() super(Entry,self).save() I couldn't make out why Entry and self are passed as arguments to super ().Can someone ple

Re: use of super

thanks Simon..I should have checked it -- http://mail.python.org/mailman/listinfo/python-list

os.path.join doubt

In windows ,I tried this p1 = "C:\Users\me\Documents" p2 = "..\Pictures\images\my.jpg" print os.path.join(p1,p2) This gives 'C:\\Users\\me\\Documents\\..\\Pictures\\images\\my.jpg' I expected I would get 'C:\\Users\\me\\Pictures\\images\\my.jpg' I thought os.path.join would join the paths more

elementwise multiplication of 2 lists of numbers

hi I have 2 lists of numbers,say x=[2,4,3,1] y=[5,9,10,6] I need to create another list containing z=[2*5, 4*9, 3*10, 1*6] ie =[10,36,30,6] I did not want to use numpy or any Array types.I tried to implement this in python .I tried the following z=[] for a,b in zip(x,y): z.append(a*b) Th

Re: elementwise multiplication of 2 lists of numbers

On Sep 20, 7:28 pm, Bruno wrote: >> A list comp comes to mind, as well as using itertools.izip thanks Bruno,thanks Gary.. Should have thought of list comprehension.. Thanks for the pointer about izip harry -- http://mail.python.org/mailman/listinfo/python-list

tix problem in ubuntu karmic

hi I posted this question in ubuntu users forum but no help was forthcoming.. I hope someone can help me here. I had been using jaunty as o.s and was coding in python 2.6. While using Tix widgets in my code I came across a bug as mentioned in https://bugs.launchpad.net/ubuntu/+source/tix/+bug/3

scheduler or infinite loop

hi I am trying to write a program to read data from a site url. The program must read the data from site every 5 minutes. def get_data_from_site(pageurlstr): h=urllib.urlopen(pageurlstr) data=h.read() process_data(data) At first, I thought of using the sched module ,but then it doesn'

Re: scheduler or infinite loop

thanks Frank > > Here is a technique that allows the loop to run in the background, in its > own thread, leaving the main program to do other processing - > > import threading > > class DataGetter(threading.Thread): > -- http://mail.python.org/mailman/listinfo/python-list

singleton problems

hi I have been trying out singleton design pattern implementations..I wrote this, class Singleton(object): _instance = None def __new__(self, *args, **kwargs): if not self._instance: self._instance = super(Singleton, self).__new__(self, *args, **kwargs) return

Re: singleton problems

thanks Steven..that was very helpful..thanks a lot harry > Since __new__ is called before the instance exists, it doesn't receive an > instance as the first argument. Instead it receives the class. While you > can call the parameter anything you like, it is conventional to call it > cls rather than

Re: singleton problems

thanks Arnold..that made it quite clear harry On Oct 3, 4:11 pm, Arnaud Delobelle wrote: > Arnaud Delobelle writes: > -- http://mail.python.org/mailman/listinfo/python-list

how to handle network failures

hi I am trying to write a DataGrabber which reads some data from given url..I made DataGrabber as a Thread and want to wait for some interval of time in case there is a network failure that prevents read(). I am not very sure how to implement this class DataGrabber(threading.Thread): def __in

how to find difference in number of characters

hi I am trying to write a compare method which takes two strings and find how many characters have changed. def compare_strings(s1,s2): pass text1="goat milk" text2="cow milk" print compare_strings(text1,text2) This must give 3 ,since 3 characters are changed between strings.I was advised

Re: how to find difference in number of characters

On Oct 9, 2:45 pm, Peter Otten <__pete...@web.de> wrote: > > What would be an acceptable time? > Thanks for the reply Peter, I was using python functions I came across the net..not cpython implementations..Probably my low config machine is also to blame..(I am no expert at judging algorithm perfo

Re: how to find difference in number of characters

On Oct 9, 4:52 pm, Peter Otten <__pete...@web.de> wrote: > > You might get more/better answers if you tell us more about the context of > the problem and add some details that may be relevant. > > Peter I am trying to determine if a wep page is updated by x number of characters..Mozilla firefox p

Re: Testing for changes on a web page (was: how to find difference in number of characters)

On Oct 9, 5:41 pm, Stefan Behnel wrote: > "Number of characters" sounds like a rather useless measure here. What I meant by number of characters was the number of edits happened between the two versions..Levenshtein distance may be one way for this..but I was wondering if difflib could do this r

can I use more than one status condition name in imaplib.status()

Hi In the signature of of imaplib.status() method MAP4.status(mailbox, names) why is the 'names ' argument plural?Can I pass more than one name to the method? I can get correct result when I call, imapclient.status('Inbox', "(UNSEEN)") or imapclient.status('Inbox', "(RECENT)") Is it possible to

imaplib AND date format

In imaplib.IMAP4.search() the search string SENTON can be used '(SENTON 22-Jun-2010)' . But the RFC 2060 defines search key as SENTON Messages whose [RFC-822] Date: header is within the specified date. and in RFC822 it is given as, date= 1*2DIGIT month 2DIGIT