🌐 Mailman 3 July 2008 - Python-list - python.org

Re: beginner's questions - manipulating text files
by Ben Finney July 2, 2008

July 2, 2008

Cédric Lucantis <omer(a)no-log.org> writes: > Le Wednesday 02 July 2008 01:16:30 Ben Keshet, vous avez écrit : > > I am trying to write a script that will search for the second and > > third appearance of the symbol '@' in a file, will read a random > > line between them, and write the line into a new file. > > If the file you're reading is not too big, you can use > file.readlines() which read all the files and returns its content as > a list of lines. Better is to iterate over the file object, getting a line each time. This works regardless of the size of the file, because it doesn't attempt to read the entirety of a large file in at once. > text.find('@') will return the position of the first occurence of > '@', or a negative value if not found. If one is interested only in *whether* text is contained within a string (and is uninterested in its position), the 'in' operator returns a boolean value. Untried code: import random separator = "@" interesting_lines = [] input_file = open("foo.txt") seen_separator_count = 0 for line in input_file: if separator in line: # Count this separator, but don't keep the line. seen_separator_count += 1 continue if seen_separator_count == 2: # We have seen exactly two lines with separators, # so we're interested in the current line. interesting_lines.append(line) if seen_separator_count >= 3: # After seeing three lines with separators, stop reading. break chosen_line = random.choice(interesting_lines) output_file = open("bar.txt", 'w') output_file.write(chosen_line) -- \ “Smoking cures weight problems. Eventually.” —Steven Wright | `\ | _o__) | Ben Finney

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beginner's questions - manipulating text files
by Ben Keshet July 2, 2008

July 2, 2008

Hi, I am a very beginner Python programmer with limited programming experience overall. I am trying to write a script that will search for the second and third appearance of the symbol '@' in a file, will read a random line between them, and write the line into a new file. So far I was only able to open the file using 'open', but I am not sure how to proceed. I tried to read it line by line using 'readline' but was not sure how to manipulate the text the way I need to. Could anyone please give me |a basic guidance as for what functions may be useful for my purpose? (e.g how to search for a string '@' in a text? how to identify its location? how to choose a random number in a defined range? how to read that line number from a text file? etc.)| || |Any help will be much appreciated (please remember that I am a super beginner).| || |Thanks.| || | |

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Attribute reference design
by chamalulu July 2, 2008

July 2, 2008

Hello. I think I'm aware of how attribute access is resolved in python. When referencing a class instance attribute which is not defined in the scope of the instance, Python looks for a class attribute with the same name. (For assignment or deletion this is not the case, thankfully.) I've been trying to understand why? What is the reason behind, or practical purpose of, this design decision? Anyone, please enlighten me. /Henrik

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detection of unplugged cable
by Oguz Yarimtepe July 2, 2008

July 2, 2008

Hi, I am tring to develeop a gui with pyqt. I need to detect whether the the cable to vga, dmi or s-video outputs are plugged or unplugged. After detection i need to run a process. How can i do this? -- Oğuz Yarımtepe

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How to identify whether a function is module scoped function or static method of a class by using its fully qualified name
by srinivasan srinivas July 2, 2008

July 2, 2008

Thanks, Srini Best Jokes, Best Friends, Best Food and more. Go to http://in.promos.yahoo.com/groups/bestofyahoo/

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Using Bluetooth Module
by Abhishek Wadhava July 2, 2008

July 2, 2008

Hi..!! I was thinking to perform bluetooth Communication with Python. So can any1 guide me from where to start...i mean any particular module or library for that, any documentations for that..etc etc...

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Re: Attribute reference design
by chamalulu July 2, 2008

July 2, 2008

On Jul 2, 1:17 am, Gary Herron <gher...(a)islandtraining.com> wrote: > No need. Also, you can define a class attribute (C++ might call it a > static attribute) and access it transparently through an instance. > > class C: > aClassAttribute = 123 > def __init__(self, ...): > ... > > c = C() > ... do something with c.aClassAttribute ... > Actually, this is why I started too look into the attribute reference mechanics to begin with. Coming from mostly C# development I think it's weird to be able to refer to class attributes (static members) through a class instance (object). But I think I'm getting the picture. Function objects lay flat in memory (some heap...). When defined inside classes they are wrapped in method objects. When refered through classes or class instances they are unbound method objects or bound method objects respectively. Am I on the right track? I still don't get why these methods show up when I dir() a class instance. /Henrik

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Re: Problem with a for loop and a list
by Bruno Desthuilliers July 2, 2008

July 2, 2008

Alexnb a écrit : > I am not sure what is going on here. Here is the code that is being run: > > def getWords(self): > self.n=0 > for entry in self.listBuffer: > self.wordList[self.n] = entry.get() > self.n=self.n+1 > print self.wordList def get_words(self): self.word_list = [e.get() for e in self.list_buffer] > This is the "listBuffer" that you see: > > self.listBuffer=[self.e1, self.e2, self.e3, self.e4, > self.e5, self.e6, self.e7, self.e8, > self.e9, self.e10, self.e11, > self.e12, self.e13, self.e14] What a fantastic naming scheme. So easy to read, understand and maintain. Congratulation, you just won the right to read "How to write unmaintainable code": http://mindprod.com/jgloss/unmain.html

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Re: Mako vs. Cheetah?
by Bruno Desthuilliers July 2, 2008

July 2, 2008

Maric Michaud a écrit : > Le Saturday 28 June 2008 06:30:50 Tim Roberts, vous avez écrit : >> Others really like the TAL scheme in Zope. >> For my taste, TAL just requires too much non-essential syntax; it >> interferes with the reading of the page. >> >> So, the folks who like TAL can go ahead and be productive with TAL, and >> I'll keep on being productive with Cheetah. > > Yes, TAL is a bit more hard and require some added learning, but tal templates > are very powerful and well structured, and they have a real advantage over > all other templating system, they are valid xhtml, So are Kid and Genshi, and they are way less verbose than TAL. And FWIW making Django's templating system xhtml compliant mostly requires redefining a couple constants to replace {% %} with <?py ?> and {{ }} with ${ }.

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convert unicode characters to visibly similar ascii characters
by Peter Bulychev July 2, 2008

July 2, 2008

Hello. I want to convert unicode character into ascii one. The method ".encode('ASCII') " can convert only those unicode characters, which fit into 0..128 range. But there are still lots of characters beyond this range, which can be manually converted to some visibly similar ascii characters. For instance, there are several quotation marks in unicode, which can be converted into ascii quotation mark. Can this conversion be performed in automatic manner? After googling I've only found that there exists Unicode database, which stores human-readable information on notation of all unicode characters ( ftp://ftp.unicode.org/Public/UNIDATA/UnicodeData.txt). And there also exists the Python adapter for this database ( http://docs.python.org/lib/module-unicodedata.html). Using this database I can do something like `if notation.find('QUOTATION')!=-1:\n\treturn "'"`. I believe there is more elegant way. Am I right? Thanks. -- Best regards, Peter Bulychev.

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