Mega Newbie Questions: Probably FAQs
I'm pretty well of a mind to pick up Python. I like it because it seems to have a fair degree of functionality and is accessible to someone without a PhD in computer sciences. This is my second day of investigation, and I'm astounded by the huge ecosystem that surrounds it. I have a number of questions that probably should be on a FAQ, but I haven't found them. I'll explain my goals and needs, perhaps someone here will have some recommendations 1) I want to write high-level apps that are db connected, networkable and cross-platform: Linux, Mac OSX, Windows. I know there are apps that can convert to Linux or Windows as stand-alone executables, is there also one that will permit me to convert to MacOSX? 1b) Are these executable completely free from the need of the average user needing to install Python. Basically, I want to write and sell "compiled" apps. 2) I want a real and native GUI. wxPython or PyQT? My concerns are about cross-platform and responsiveness of GUI. I suspect that this will be one of the gravest issues for the long run. 3) Can someone recommend a good framework that will enable me to keep things well sorted out, and easy to maintain as my apps grow? (I'm considering MVC, but have no idea how to apply it until I've gone beyond "Hello World"). 4) There are a lot of books and tutorials out there, but they are of the proof-of-concept type. Specifically, a tutorial might teach me Hello World, but not really care about the framework, because it's a very simple item, and the point is simply to get me coding. I'd like to start off with an established, tested and reputable system whose habits I can ingrain from day one, rather than figure it out later. Can someone recommend a good book, or your favourite tutorials? Perhaps even one that assumes MVC as the framework? 5) Following the above, is there a framework that assumes tcp/ip udp networking, database connectivity? My first app will be in large part a networkable database type app where two or more users can share the same file concurrently. 6) Since I've been a web-developer for a long time (over 10 years), I never properly learned OOP. Recommended tutorials? 7) I'm developing on WinXP and for the IDE, I'm considering theKompany.com's BlackAdder, Komodo or Eclipse. Any very strong negatives in regards to either of these? 8) Can anyone speak to the point, or point out a useful comparison between Python and RealBasic? Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Mega Newbie Questions: Probably FAQs
ajaksu wrote: > Hoping this helps more than confuses, Thanks, these were the sort of answers I was looking for. I've programmed in Basic, AppleScript, Pascal and Usertalk (Userland Frontier), I've got a sense for development, it's just been a very, very long time ago. I do intend to start small and build up, but I want to front load my learning curve, usually makes the other side of the curve more productive. -- http://mail.python.org/mailman/listinfo/python-list
Re: Mega Newbie Questions: Probably FAQs
ajaksu wrote: > Zeph wrote: And I'd research a bit about decompiling those executables, > might be easier (or harder, in my case) than you thought :) Are you saying that generally python code is insecure? It hadn't occurred to me, but I want to play in a fairly competitive field, and I'd hate to have a competitor rip my app. > Framework... MVC... not my area, sorry. I think a better word might have been "methodology", for example, as a Coldfusion developer, I enjoy using Fusebox. -- http://mail.python.org/mailman/listinfo/python-list
Re: Mega Newbie Questions: Probably FAQs
Zeph wrote: >> 3) Can someone recommend a good framework that will enable me to keep >> things well sorted out, and easy to maintain as my apps grow? (I'm >> considering MVC, but have no idea how to apply it until I've gone >> beyond "Hello World"). Yu-Xi Lim wrote: > Framework for what kind of apps? Web, native GUI, client-server, etc? > MVC is an abstract architecture rather than a specific implementation. > Even so, many implementations rarely employ a purely MVC design. Native GUI with some client-server abilities. Basically, it's a database-inventory sort of thing with some pretty intense reporting. Call it a productivity app--no need for intense graphics or massive computation. Fundamentally, what I want is to be able to distribute a "regular app", mainly for the Windows market, but I also want to offer it to the Mac and Linux crowd--on one code base if possible. I have on a number of occasions downloaded apps that required that Visual Basic, or .Net or whatever runtimes be installed. I've never liked or trusted these kinds of apps. Regardless of the quality that the particular thing may have had, I didn't trust it and didn't like all of the extra clutter that went along with it. This is why I'd prefer to deliver some sort of stand alone solution--or at least something that appears as such. Fundamentally, I want to put out a solid, slick and professional product. Is Python still a good choice for me? Back to the question: When I speak of framework, maybe I should have used the term "methodology". I have excellent methods for coding my web-apps (I like Fusebox) but not having created anything significant in another language from scratch for over 10 years, I wouldn't know how to start organizing my stuff so that it's long-term maintainable. > The size of the Python community is huge compared to RealBasic. And > you'll benefit from that alone by better answers to your questions, > better documentation, and better 3rd party libraries. Excellent points. > Side note: You seem like you've researched a bit, but unfortunately been > affected by the swirl of buzzwords. While there are usually valid > reasons for particular technologies to have so much hype behind them, > you should not neglect the alternatives. They may be the answer you seek. Yes. That's the problem with being a newb: you don't know what you don't know, then when you do, it's obvious. I'm still seeing only the surface. One question that does come to my mind is that of the notion of decompiling or reverse engineering. Based on a comment someone made earlier, is this a significant concern that I should have, if I want to ship commercial software? The stage I'm at right now is that I'm on the fence between REALbasic and Python. Here's how I see it, relevant to my situation: REALbasic Pros: A fairly rich system, excellent GUI, spits out a binary executable for Win, Mac and Linux. One code base. Well documented, ever evolving. Relatively reasonably priced for commercial purposes. Cons: Closed source (what if they're bought out?) I'm not sure that I can trust my investment of time to last 10 years. The language and IDE is a tad strange to me. It has the word "Basic" (read: cheap, half-assed, not-a-real-app) in it, which is not a particularly good term to use in a pitch. Unknown: Learning curve? Long-term value? Level of support? Python Pros: Free. Open source. Deep. Flexible. Rich community and third party stuff. Well documented. Cons: Interpreted. Unknown: Secure (meaning not easily reverse engineered) code? Performance? Further thoughts? -- http://mail.python.org/mailman/listinfo/python-list
Re: How to tell if you're running on windows?
On Dec 4, 10:46 am, Roy Smith wrote: > I'm using 2.5.1. How can I tell if I'm running on windows? The > obvious answer, platform.system(), gets complicated. On the python > that comes with cygwin, it returns 'CYGWIN_NT-5.2-WOW64', but I've got > a native windows build of python where it returns 'Microsoft'. > > The real problem I'm trying to solve is whether to build a LIBPATH > environment variable with ';' or ':' delimiting the entries. On the > cygwin build, os.pathsep returns ':', which isn't really correct. If > you use that, you end up building paths that look like c:foo:c:bar. > It should be c:foo;c:bar The Cygwin shell uses what appears to be its own pseudo-filesystem. If you open your Cygwin shell window and type echo $PATH you will see completely different results from the Windows command shell's PATH env variable, and you'll see the path sep is indeed ':'. Cygwin also seems to put drive mount points in /cygdrive/ so you will have for example "/cygdrive/c/foo:/cygdrive/c/bar" instead of "C: \foo;C:\bar". For python *outside* of Cygwin, on Windows, I assume os.path.pathsep is ';'. - zeph -- http://mail.python.org/mailman/listinfo/python-list
Re: Difference between mutex.mutex and threading.Lock
The mutex class (and module) should not be used, since it is, as you said, deprecated for 3.0. Like the docs say, it "does not require (or imply) threading or multi-tasking, though it could be useful for those purposes." The mutex class' lock() method takes a function and args and if the mutex is unlocked, calls the function with args immediately, or if locked, adds to a queue and waits for it to be unlocked The threading.Lock object is a lock shared between threads. For example, if you have two threads (thread1 and thread2) and thread1 does lock.acquire() and thread 2 calls lock.acquire(), thread2 will block until thread1 calls lock.release(), then thread2 will get a chance to run its critical code section, then call lock.release(). - zeph -- http://mail.python.org/mailman/listinfo/python-list
Re: How to timeout when waiting for raw_input from user ?
Here's what I came up with, though it only asks once question then
quits depending on the answer or lack thereof. And while, yes, you
can't interrupt a raw_input call from a timer, providing for a blank
line (user hitting enter) is a way around it:
import threading import Timer
from random import randrange
import sys
def multiply_game():
a = randrange(1,10)
b = randrange(1,10)
answer = raw_input('what is %s * %s?: ' % (a,b))
if not answer:
return
timer.cancel()
if str(answer) == str(a * b):
print 'right! :D'
else:
print 'wrong :('
def tooslow():
print "\ntoo slow :(\nHit ENTER to quit"
timer = Timer(30, tooslow) # 30 seconds
timer.start()
multiply_game()
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Re: Organization of GUIs
I highly recommend reading the Cocoa documentation, which has volumes on all sorts of things like this. Here's a link that talks about views in that context, and should give you more ideas about well- designed GUI layouts: http://bit.ly/6b8PYh -- http://mail.python.org/mailman/listinfo/python-list
Re: What is the significance of after() in this code?
On Dec 6, 8:46 pm, Benjamin Kaplan wrote:
> On Sun, Dec 6, 2009 at 10:29 PM, W. eWatson wrote:
> > See Subject.
> > def StackImages(self):
> > self.Upload("P")
> > self.after_id = self.master.after(1,self.GetFrameOne)
> > --
> >http://mail.python.org/mailman/listinfo/python-list
>
> I think this is close to winning an award for "least information
> provided". How are we supposed to know with the information you gave
> us? We don't know what package you're using, what type anything is, or
> even the purpose of that method. Try putting this line in there
> somewhere
> print type(self.master)
>
> and then open up the interactive interpreter, import whatever you need and do
> help(.after)
True, though by *context* the after method looks like it takes a time
(probably in milliseconds, given its size), and a method, and calls
the method after that amount of time, and returning some process/
thread id to self.after_id. Though if that's right, we still don't
know if its synchronous or not, if its calling it in a new thread or a
new process, etc etc.
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Re: test if an input string starts with a python expression
It sort of sounds like you want a templating system: http://wiki.python.org/moin/Templating -- http://mail.python.org/mailman/listinfo/python-list
Re: switch
>
> Even better (well, shorter!):
> options = {"a" : do_a, "b",do_b, "c", do_c}
> options.get(option, do_default)()
>
You can also make it something callable like so, which is a little
more compact if you need to reuse it a lot:
>>> def do_a(x): print "a:", x
...
>>> def do_b(x): print "b:", x
...
>>> def do_c(x): print "c:", x
...
>>> do_something = {"a":do_a, "b":do_b, "c": do_c}.get
>>> do_something('a')(4)
a: 4
>>> do_something('c')(5)
c: 5
>>> do_something
>>> do_something('d')
>>> do_something('d')(5)
Traceback (most recent call last):
File "", line 1, in
TypeError: 'NoneType' object is not callable
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Re: How do I Block Events in wxPython
The wxPython wiki actually has a page on dealing with long running tasks called from event handlers called (surprise surprise): http://wiki.wxpython.org/LongRunningTasks Hint: the second to last example on that page has the clearest example - using a worker thread object to do your DoEfficiency() function. I also don't think you want to disable so many event handlers, do you? Nothing will respond to inputs as long as that process is running (assuming you aren't running it in another thread.) -- http://mail.python.org/mailman/listinfo/python-list
Re: Perl to Python conversion
Python and Perl often have different design idioms - learning to write *well* in a language involves understanding those idioms, and being able to translate between languages involves understanding the source language well enough to understand the intent of the program's code (even if its poorly written), and understanding the target language well enough to translate the intent into a design fitting the language. Perl and Python have enough syntactic similarities that you could, if you wanted, just translate the program verbatim. Overall, I would recommend adding your imperial->metric functionality to the Perl code for now, and on your free time work on translating to Python, so you don't feel rushed to get it finished. You will probably come to understand the Perl code better after having worked with it and been involved in a hands-on way with it. Likewise, you will become even more familiar with it and with Python as you learn how to translate the application. -- http://mail.python.org/mailman/listinfo/python-list
Re: Moving from PHP to Python. Is it Possible
Hi Sancar, 1) PHP does some really nasty things in how it treats globals, and you will have to break yourself of those sorts of habits -- Python offers much cleaner alternatives, like grouping similar functionality into modules which can be imported; the import functionality in python is pretty flexible. Python won't pack a ton of garbage into a giant, global 'dictionary' (what python calls associative arrays). There are modules (bundled of code) which you can import to handle your needs. 2) Check out the traceback[1] module for retrieving the traceback info for logging to a file, and cgitb[2] modules for printing the traceback as HTML to your browser. 3) http://docs.python.org/ is a great place to start - it has a lot of well written and generally thorough documentation with examples 4) It's better to collect all your eventual output into a string that you print - there are examples at [3]. You can import from other modules as needed (even conditionally), grow your string for output, then finally print it like (this example was adapted from one found on [3]): output = '' output += 'My Page' output += '' output += 'Powers of two\n' for n in range(1,11): output += ''+str(2**n)+'' output += '' print output You can copy-paste this right into your Python interactive shell to see the output. Note: += is inline string concatenation. 5) You can get form state from the cgi module[4] and FormStorage object, and you can get server environment data from the os.environ[5] dictionary; Good luck and keep on learning! :-) - zeph References: 1: http://docs.python.org/library/traceback.html 2: http://docs.python.org/library/cgitb.html 3: http://gnosis.cx/publish/programming/feature_5min_python.html 4: http://docs.python.org/library/cgi.html 5: http://docs.python.org/library/os.html#process-parameters -- http://mail.python.org/mailman/listinfo/python-list
Re: Moving from PHP to Python. Is it Possible
On Dec 11, 8:58 am, MRAB wrote:
> output = ['']
> output.append('My Page')
> output.append('')
> output.append('Powers of two\n')
> for n in range(1, 11):
> output.append('%s' % (2 ** n))
>
> output.append('')
> print ''.join(output)
Agreed (I might join on '\n' though), I was just trying to introduce
as few new concepts as possible :)
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Re: parallelpython 1.5.7 crash
I looked in the browsable svn repo for parallel python at
http://parallelpython.googlecode.com/svn/trunk/
1) OverflowError: long int too large to convert to int
This is a bug in their code (comments are mine) in pytransport.py:
size_packed = self.r.read(struct.calcsize("!Q")) # reads in 8-
character string
msg_len = struct.unpack("!Q", size_packed)[0] # unpacks to a long
value, e.g. "12345678" -> 3544952156018063160L
msg = self.r.read(msg_len)#
3544952156018063160L is too long for file.read, which I presume must
be able to cast as an int
As an example:
>>> sys.stdin.read(3544952156018063160L)
Traceback (most recent call last):
File "", line 1, in
OverflowError: long int too large to convert to int
2) UnboundLocalError: local variable 'sresult' referenced before
assignment
This is another bug in their code. This is an error in pp.py (again,
comments are mine, some code omitted for brevity):
try:
# ...snip...
sresult = worker.t.receive() # sets sresult
except:
if self.__exiting:
return
else:
# at this point, __run doesn't return, but sresult was not defined
since the
# execution was unwound because, presumable, the first fatal you
got, the OverflowError
sys.excepthook(*sys.exc_info())
# ...snip...
job.finalize(sresult) # UnboundLocalError here from missing sresult
You can submit these as a bug report to the author if you want - feel
free to copy-paste or link to this post :-)
- zeph
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