[Tutor] Reading only a few specific lines of a file

[Marilyn Davis]

(I'm sorry for the duplicate, Alan.)

On Fri, May 23, 2008 3:49 am, Alan Gauld wrote:

> "Jason Conner" <jasonbconner at gmail.com> wrote
>
>
>> building a program that will take a text file, search for a string in
>> that text file. Once it finds the string its looking for, I want to put
>> the next five lines of text into a variable. Here's what I have so far:
>>
>> def loadItem(self, objectToLoad): x = 0 wordList = [] fobj = file()
>
> This does nothing. file() is just an alias for open()
>
>
>
>> fobj.open("itemconfig.txt", 'rU')
>>
>> for line in fobj.readline():
>
> And you can iterate over the file itself so this could become:
>
>
> for line in file(("itemconfig.txt", 'rU'):
>
>
>> if line == objectToLoad: while x != 5 for word in line.split():
>> wordList.append(word) x += 1
>
> This isn't quite what you said above in that you didn't mention
> storing the individual words...
>
>>
>> thing = item(wordList[0], wordList[1], wordList[2], wordList[3],
>> wordList[4])
>
> But this could just be:
>
>
> thing = line.split[:5]   # use slicing to get first 4 items
>
>> itemList.append(thing)
>
> or even make it all one line here...
>
> Now to get the next 4 lines as well set a flag/counter. say linecount.
> Set it to 0 at the top then
>
>
> linecount = 0 for line in file("itemconfig.txt", 'rU'): if line ==
> objectToLoad or linecount > 0: if linecount == 0: linecount = 5   # set
> linecount on first line itemList.append(line.split()[:5])
> linecount -= 1

I always go for readability.  So I like "for x in range(5):" to go 5
times.  I'm not sure what we should be doing 5 times either.

Similarly, for readability, I choose the if/elif/else form of switch
replacement.

Also, I don't like to see the obfuscated forms of the conditional
operator.  Heck, I'm not even crazy about the Python conditional in 2.5.

I like to say "The point of a programming language is to communicate with
other engineers (in a language that also the computer understands)."

I hope you like these thoughts.

Marilyn Davis

>
>
> HTH,
>
>
> --
> Alan Gauld
> Author of the Learn to Program web site
> http://www.freenetpages.co.uk/hp/alan.gauld
>
>
>
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