🌐 Mailman 3 November 2012 - Tutor - python.org

Wave module
by Alex Krycek Feb. 12, 2015

Feb. 12, 2015

Hello, I'm trying to join two .wav files with the wave module. But when I try to use wave.open(filename, "rb") I receive the following error: Traceback (most recent call last): File "<stdin>", line 1, in <module> File "F:\PortablePython1.0\lib\wave.py", line 483, in open return Wave_read(f) File "F:\PortablePython1.0\lib\wave.py", line 162, in __init__ self.initfp(f) File "F:\PortablePython1.0\lib\wave.py", line 143, in initfp self._read_fmt_chunk(chunk) File "F:\PortablePython1.0\lib\wave.py", line 264, in _read_fmt_chunk raise Error, 'unknown format: %r' % (wFormatTag,) wave.Error: unknown format: 85 I read somewhere that there are various wave formats, only some supported by Python. Is this true? If so, is there any way I can convert my wave files into a supported kind? Thanks!

3 2

getUncPath(mappedDrive)
by Albert-Jan Roskam Jan. 31, 2014

Jan. 31, 2014

Hi, Is there a function that takes a file path with a mapped drive (z:\blah) and returns the associated UNC path (\\server\share\ding\dang\dong\blah)? I looked in os.path, but it doesn't seem to have this. The link below seems to be a solution (code in the bottom of the page), but I can't install win32com.client in the office :-( Is there any built-in function? http://stackoverflow.com/questions/2244767/python-check-network-map Thanks! Regards, Albert-Jan ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

4 10

How to unpack python-dateutil-2.0.tar.gz
by Richard D. Moores Sept. 5, 2013

Sept. 5, 2013

Python 3.2.3 64 bit MS Windows 7 Home Premium 64-bit SP1 I see python-dateutil recommended here from time to time, so I thought I'd try it out. I downloaded python-dateutil-2.1.tar.gz from http://pypi.python.org/pypi/python-dateutil but have forgotten how to unpack a .tar.gz file. Please remind me. Thanks, Dick Moores

7 20

how to struct.pack a unicode string?
by Albert-Jan Roskam Jan. 3, 2013

Jan. 3, 2013

Hi, How can I pack a unicode string using the struct module? If I simply use packed = struct.pack(fmt, hello) in the code below (and 'hello' is a unicode string), I get this: "error: argument for 's' must be a string". I keep reading that I have to encode it to a utf-8 bytestring, but this does not work (it yields mojibake and tofu output for some of the languages). It's annoying if one needs to know the encoding in which each individual language should be represented. I was hoping "unicode-internal" was the way to do it, but this does not reproduce the original string when I unpack it.. :-( # Python 2.6.4 (r264:75708, Oct 26 2009, 08:23:19) [MSC v.1500 32 bit (Intel)] on win32 import sys import struct greetings = \ [['Arabic', [1575, 1604, 1587, 1604, 1575, 1605, 32, 1593, 1604, 1610, 1603, 1605], 'cp1256'], # 'cp864' 'iso8859_6' ['Assamese', [2472, 2478, 2488, 2509, 2453, 2494, 2544], 'utf-8'], ['Bengali', [2438, 2488, 2488, 2494, 2482, 2494, 2478, 2497, 32, 2438, 2482, 2494, 2439, 2453, 2497, 2478], 'utf-8'], ['Georgian', [4306, 4304, 4315, 4304, 4320, 4335, 4317, 4305, 4304], 'utf-8'], ['Kazakh', [1057, 1241, 1083, 1077, 1084, 1077, 1090, 1089, 1110, 1079, 32, 1073, 1077], 'utf-8'], ['Russian', [1047, 1076, 1088,1072, 1074, 1089, 1090, 1074, 1091, 1081, 1090, 1077], 'utf-8'], ['Spanish', [161, 72, 111, 108, 97, 33], 'cp1252'], ['Swiss German', [71, 114, 252, 101, 122, 105], 'cp1252'], ['Thai', [3626, 3623, 3633, 3626, 3604, 3637], 'cp874'], ['Walloon', [66, 111, 110, 100, 106, 111, 251], 'cp1252']] for greet in greetings: language, chars, encoding = greet hello = "".join([unichr(i) for i in chars]) #print language, hello, encoding # prints everything as it should look endianness = "<" if sys.byteorder == "little" else ">" fmt = endianness + str(len(hello)) + "s" #https://code.activestate.com/lists/python-list/301601/ #http://bytes.com/topic/python/answers/546519-unicode-strings-struct-files #packed = struct.pack(fmt, hello.encode('utf_32_le')) #packed = struct.pack(fmt, hello.encode(encoding)) #packed = struct.pack(fmt, hello.encode('utf_8')) packed = struct.pack(fmt, hello.encode("unicode-internal")) print struct.unpack(fmt, packed)[0].decode("unicode-internal") # UnicodeDecodeError: 'unicode_internal' codec can't decode byte 0x00 in position 12: truncated input Thank you in advance! Regards, Albert-Jan ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

5 14

memoize, lookup, or KIS?
by Albert-Jan Roskam Dec. 10, 2012

Dec. 10, 2012

Hi, I have a function that converts a date value, expressed as the number of seconds sinds start of the gregorian calendar, into a human-readable format (typically an iso-date). So if a record contains x date values, and a data set contains y records, the number of function calls are x * y. Imagine a data set with 1M records with dob and enrollment_date in in it: the number of function calls is huge (well, 2M). I was reading about memoize decorators the other day and I realized that this function might benefit from memoizing, or a lookup table. On the other hand, it might complicate the code too much, so it might be better to Keep It Simple (KIS). Is the code below a sound approach? I believe that, in effect, it uses a memoization approach (as it is a slowly growing lookup table). import datetime class Test(object): def __init__(self): self.isoDateLookup = {} self.lookupCount = 0 def spss2strDate(self, gregorianDate, fmt="%Y-%m-%d", recodeSysmisTo=""): """ This function converts internal SPSS dates (number of seconds since midnight, Oct 14, 1582 (the beginning of the Gregorian calendar)) to a human-readable format """ MAXLOOKUP = 10**6 try: if not hasattr(self, "gregorianEpoch"): self.gregorianEpoch = datetime.datetime(1582, 10, 14, 0, 0, 0) if fmt == "%Y-%m-%d" and len(self.isoDateLookup) <= MAXLOOKUP: try: result = self.isoDateLookup[gregorianDate] self.lookupCount += 1 except KeyError: theDate = self.gregorianEpoch + datetime.timedelta(seconds=gregorianDate) result = datetime.datetime.strftime(theDate, fmt) self.isoDateLookup[gregorianDate] = result return result else: theDate = self.gregorianEpoch + datetime.timedelta(seconds=gregorianDate) return datetime.datetime.strftime(theDate, fmt) except OverflowError: return recodeSysmisTo except TypeError: return recodeSysmisTo except ValueError: return recodeSysmisTo if __name__ == "__main__": import random t = Test() someDate = 11654150400.0 aDay = 24 * 60 * 60 random.seed(43210) for i in xrange(10**3): randDate = random.randint(0, 10**3) * random.choice([aDay, -aDay]) + someDate t.spss2strDate(randDate) print t.lookupCount Regards, Albert-Jan ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

4 6

Pypi entry points
by Albert-Jan Roskam Dec. 3, 2012

Dec. 3, 2012

Hi, I am reading The Hitchhiker's Guide to Packaging 1.0 documentation, specifically http://guide.python-distribute.org/creation.html. I am struggling to understand the section about Entry Points. This appears to be a way to include extra functionality in a program, without the need to actually include it in the tar.gz file. Or, as the website says: "[A] pretty easy and simple way to allow other packages to register something that you want to know. Extra plugins, extra render methods, extra functionality you want to register in your web application, etcetera." I find the code examples hard to understand. I'd expect that it'd be steps like "in the middle of the setup, download and unzip file xxxx.zip from website http://blaaah.eu. How does this work? Regards, Albert-Jan ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

2 1

(no subject)
by Tara Nicholson Dec. 3, 2012

Dec. 3, 2012

Hi, im trying to write a script which randomly generates 10,000 points(x,y) in the unit square(so range between 0 and 1 for both x and y).so far I have written the code below in red, however it only produces one random point. How do I get it to repeat this so it produces 10,000 different random points?Thankyouuu, Tara. import mathimport randomrandom.seed() x=random.uniform(0,1)y=random.uniform(0,1) for i in range(0,1): for j in range(0,1): print (x,y)

7 8

Need a Python tutor
by Oxford Learning Centre Nov. 30, 2012

Nov. 30, 2012

Hi there My son is in first year Engineering & he needs help with reviewing for his final next week on computer programming using Python language. Please if u have or know any one who can help him that will be a great help. He is in school in Hamilton Ontario , but you can reach me either by phone 9052571207 or by e-mail. Thanks Saly Beshara Centre Director Oxford Learning Centre Oakville N/E 380 Dundas St. East Unit D-8 905-257-1207 www.oxfordlearning.com Sent from my iPad

2 1

Re: [Tutor] Dynamic TKinter widgets?
by ALAN GAULD Nov. 28, 2012

Nov. 28, 2012

CC'ing the list... I know you can use images instead of text with Labels, like you can with Buttons. >The advantage of a Text widget, in this case, is that you can use both in the same widget. >That way, I don't need to worry about how widgets are displayed, shuffled around, and >undisplayed during runtime. One widget should handle everything. > >Don't get hung up on the number of widgets. In the scheme of things widgets are not expensive. Create them as you need them, delete them when you are done. Layout managers are there to manage the layout for you. if you can define the layout in terms of a grid then you can fill the grid with blanks to hold the shape and add/remove widgets as you like. If you use pack you can either force the containing frame to a fixed size or allow it to grow/shrink with the widgets. Either approach can work. This is standard? That's interesting to know. The biggest issue I'm having here is scalability. >Each new spread is going to need a new frame widget, which in turn will need >(number of cards in spread)*2 more widgets. > >But that's how many? If its getting up beyond a couple of thousand then you might have a problem. If its less than a hundred its not an issue. In between you might want to be a bit clever. As noted above, the Text widget solution only needs one. > >Actually it probably needs more. Each image is a widget too, so you just organise the widgets inside a Text instead of inside a Frame or Canvas. All these things are just containers for more widgets. Frames are designed to hold widgets, end of story. Text is designed to *display* images and text - usually within a Frame. Canvas is designed to *display* images and graphics shapes. If you want your images joined or surrounded by lines/circles etc then go with Canvas. If you need to include explanatory text around the images use a Text. If you want to create a reusable widget that you can use in multiple screens or hot swap with other variants of the same go with a Frame and build a display widget hierarchy. If you just want to display a bunch of images it doesn't matter much which one you pick. I repeat, don't sweat over the widget count, that's not usually an issue. Alan G.

2 3

Question about the raw string
by JiangShan Nov. 28, 2012

Nov. 28, 2012

Hi everyone, I am studying the python 3 and I am confused about the raw string. Why does the python interpreter do not escape the single backslash before the quotes even I add a "r" before the string. The following is an example: >>> print(r"\") SyntaxError: EOL while scanning string literal >>> print(r"\\") \\ >>> Jiang Shan

2 1