Sort lines in a plain text file alphanumerically
Devyn Collier Johnson
devyncjohnson at gmail.com
Tue Aug 6 06:38:08 EDT 2013
On 08/05/2013 11:12 PM, Joshua Landau wrote:
> On 6 August 2013 03:00, Devyn Collier Johnson <devyncjohnson at gmail.com
> <mailto:devyncjohnson at gmail.com>> wrote:
>
> I am wanting to sort a plain text file alphanumerically by the
> lines. I have tried this code, but I get an error. I assume this
> command does not accept newline characters.
>
>
> HINT #1: Don't assume that without a reason. It's wrong.
>
> >>> file = open('/home/collier/pytest/sort.TXT', 'r').read()
>
>
> HINT #2: Don't lie. "file" is not a file so you probably shouldn't
> call it one. It's the contents of a file object.
>
> >>> print(file)
> z
> c
> w
> r
> h
> s
> d
>
>
> >>> file.sort() #The first blank line above is from the file. I do
> not know where the second comes from.
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> AttributeError: 'str' object has no attribute 'sort'
>
>
> HINT #3: *Read*. What does it say?
>
> AttributeError: 'str' object has no attribute 'sort'
>
> Probably your problem, then, is that a 'str' object has no attribute
> 'sort'. That's what it says.
>
> "file" is a "'str' object". You are accessing the 'sort' attribute
> which it doesn't have.
>
> I had the parameters (key=str.casefold, reverse=True), but I took
> those out to make sure the error was not with my parameters.
>
>
> HINT #4: Don't just guess what the problem is. The answer is in the error.
>
> Specifically, I need something that will sort the lines. They may
> contain one word or one sentence with punctuation. I need to
> reverse the sorting ('z' before 'a'). The case does not matter
> ('a' = 'A').
>
> I have also tried this without success:
>
> >>> file.sort(key=str.casefold, reverse=True)
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> AttributeError: 'str' object has no attribute 'sort'
>
>
>
>
> So you want to sort your string by lines. Rather than trying to abuse
> a .sort attribute that patently doesn't exist, just use sorted OR
> convert to a list first.
>
> sorted(open('/home/collier/pytest/sort.TXT'), key=str.casefold,
> reverse=True)
>
> Because it's bad to open files without a with unless you know what
> you're doing, use a with:
>
> with open('/home/collier/pytest/sort.TXT') as file:
> sorted(file, key=str.casefold, reverse=True)
Thanks for the advice Joshua. I find these tips very useful. However,
how would I close the files, or would they close after the "with"
construct is complete?
Mahalo,
DCJ
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