🌐 Mailman 3 July 2010 - Python-list - python.org

Sine wave?
by EC Nov. 25, 2013

Nov. 25, 2013

Ive been banging my head against the wall for the past few days trying to generate a sine wave... My math skills arent the best, I'll admit, and I think I'm going crosseyed trying to understand this... I *think* the following code should work but it outputs some really weird stuff. I'm sorta new so please help if you can! Thank you Eric #------------------------------------------- import math import wave import string pi = math.pi sin = math.sin cos = math.cos #init output and related vars sr = 44100 Outfile = wave.open("outfile.wav", "w") Outfile.setnchannels(1) Outfile.setsampwidth(4) Outfile.setframerate(sr) Outfile.setcomptype("NONE", "Uncompressed") Outtemp = [] Outstr = "" def get_phase(curphs, freq): phinc = (freq*1.0000/sr*1.0000)*360 phase = curphs + phinc if phase >= 360: phase -= 360 elif phase < 0: phase += 360 return phase def gen_wav(sec, freq, ampcent): numsamp = sec*sr amp = (ampcent*1.0000/100)*32767 i = 0 temp = [] t = 0 curphase = 0 while i < numsamp: curphase = get_phase(curphase, freq) t = int(round(amp*sin(2*pi*curphase))) temp.append(t) i+=1 return temp Outtemp = gen_wav(.01, 440, 75) Outstr = string.join(map(str, Outtemp), ",") print Outstr Outfile.writeframes(Outstr) Outfile.close()

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by Dvalve.com Nov. 22, 2013

Nov. 22, 2013

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Invalid syntax with print "Hello World"
by Henrik Bechmann Nov. 14, 2013

Nov. 14, 2013

obviously total mewbiew: My first program in Python Windows print "Hello World" I select Run/Run Module and get an error: Syntax error, with the closing quote highlighted. Tried with single quotes as well. Same problem. Can someone explain my mistake? Thanks, - Henrik

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Re: Proposal: [... for ... while cond(x)]
by Eighty Sept. 26, 2013

Sept. 26, 2013

Terry Reedy wrote: > whereas the analogous expansion of your proposal > > for x in xs: > while cond(x): > yield e(x) > > is an infinite loop and not at all what you mean. You're right. The syntax is ambiguous. I agree it's not a good idea, now. :) > x for x in xs while cond(x) if blah(x) > x for x in xs if blah(x) while cond(x) > x*y for x in xs while cond(x) for y in ys These wouldn't be a problem. "... for x in xs while cond(x) ..." would be transformed into "... for x in takewhile(cond, xs) ..." which could be applied to an if thingy if you first transform "... for x in xs if cond(x) ..." into "... for x in filter(cond, xs) ...".

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mutlifile inheritance problem
by maurelius01＠hotmail.com Sept. 21, 2013

Sept. 21, 2013

I have classes defined in different files and would like to inherit from a class in file A.py for a class in file B.py but am running into problems. I'm using Python 1.5.2 on Windows NT Here's a specific example: ************************ file cbase01.py: class CBase: def __init__(self): self.cclass = None print "cbase" class CImStream(CBase): def __init(self): CBase.__init__(self) print "CImStream" ************************* in file wrappers_A01.py: import cbase01 reload(cbase01) class ImStream_SavedBitmaps(cbase01.CImStream): def __init__(self): cbase.CImStream.__init__(self) print "SavedBitmaps" ************************** in file sequencer01.py import cbase01 # the offending lines, program works reload(cbase01) # if I comment these out. class Sequencer: def Append(self, item): pass ***************************** in test02.py import wrappers_A01 reload(wrappers_A01) import sequencer01 reload(sequencer01) x0 = wrappers_A01.ImStream_SavedBitmaps() *************************************************************** If I run test02 I get the traceback Traceback (innermost last): File "<string>", line 1, in ? File "D:\PythonCode\pna\eyeTracking\tests\test02.py", line 15, in ? x0 = wrappers_A01.ImStream_SavedBitmaps() File "D:\PythonCode\pna\eyeTracking\tests\wrappers_A01.py", line 21, in __init__ cbase.CImStream.__init__(self) TypeError: unbound method must be called with class instance 1st argument Any ideas what I am doing wrong? Thanks, Marc

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can't find win32api from embedded pyrun call
by Jim Sept. 6, 2013

Sept. 6, 2013

I am trying to figure out how to embed Python in a little C++ Windows console app. Here's the code: // Py_Initialize(); Py_InitializeEx(0); PyRun_SimpleString("from win32com.client import *"); Here's what it does on the last line: File "D:\Python\Lib\site-packages\win32com\__init__.py", line 5, in ? import win32api, sys, ok ImportError: No module named win32api The same line runs fine in IDLE or at the command prompt. It also runs without complaint if I run a release version of the app. To build the debug version I had to build python42_d.lib/dll myself. The reason I can't call PyInitialize is that it crashes with an "invalid signal" error. I don't think it's a path issue -- I've checked system path, sys.path, pythonpath env var, and the pythonpath entry in the registry, all of them loaded with directories including the one with win32api.pyd. Besides, if it were an install or path problem, why would it work at the command prompt? Could it be a problem with the debug lib I built? Any suggestions are welcome. -- Jim

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Download Visual Studio Express 2008 now
by Martin v. Loewis Aug. 29, 2013

Aug. 29, 2013

Microsoft has just released Visual Studio 2010, along with its free (of charge) Express edition. Following a tradition, they are likely to withdraw support and availability for VS 2008 Express some time in the future. Python 2.6, 2.7, and 3.1 are all built with that release (i.e. 2008). Because of another long tradition, Python extension modules must be built with the same compiler version (more specifically, CRT version) as Python itself. So to build extension modules for any of these releases, you need to have a copy of VS 2008 or VS 2008 Express. If you are planning to build Python extension modules in the next five years, I recommend that you obtain a copy of VS Express, just in case Microsoft removes it from their servers. As mentioned, it's free of charge. When downloading it for later use, it's probably best to get the offline ISO image release, available from http://www.microsoft.com/express/Downloads/#2008-All Disclaimer: I'm not connected with Microsoft or its release process. Any claim on future actions that Microsoft may take is purely hypothetical. Regards, Martin

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Best Python book(s) for a pre-teen?
by snarflemike＠yahoo.com Aug. 1, 2013

Aug. 1, 2013

Hi all, My son is 11 and wants to try programming, partly because it's what I do for a living. Even though I don't (yet?) use or even know Python, through some unexplainable thought process I've decided it would be a good language to start him off with. I've downloaded 2.2.2 and played around with it for a bit, and I would now like to hand him a book (with my guidance as needed) and say "go have fun!" Is there a book that would be suitable for this approach (again, assuming I'm around to help out as needed)? One other question -- I'd like him to be able to do simple graphics fairly early, since I think it makes the whole self-learning process much more interesting. I'm talking about things like points, lines, circles, fills, etc. Is there a binding to the Win32 graphics primatives in 2.2.2, or can I find one someplace? If this is a RTFM question, any pointers to TFM chapter, etc would be appreciated! Thanks for any guidance. I'm sure I'll end up having at least as much fun as he does. Mike

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Q: "Best" book for teaching
by grkuntzmd＠gmail.com July 27, 2013

July 27, 2013

I am considering teaching an "introduction to programming" course for continuing education adults at a local community college. These would people with no programming experience, but I will require a reasonable facility with computers. What would be a good book to use as the text for the course? Thanks.

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Tutorials on Jinja
by Saurabh July 15, 2013

July 15, 2013

Hi All, I am trying to move my application on a MVC architecture and plan to use Jinja for the same. Can anyone provide me with few quick links that might help me to get started with Jinja? Thanks, Saby

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