Newbie with sort text file question

Bob Gailer bgailer at alum.rpi.edu
Mon Jul 14 15:10:39 CEST 2003


At 03:12 PM 7/13/2003 -0600, Andrew Dalke wrote:

>Bob Gailer:
> > [Pipeline]
>
>Huh.  Hadn't heard of that one before.  Thanks for the pointer.

Since I am developing the Python version of Pipeline I wonder if you have 
any interest in it? Would like to be an early recipient?

>(And overall, nice post!)
>
> > The Python version:
>
>Some stylistic comments
>
> > input = file('c:\input.txt')
>
>Since 'input' is a builtin, I use 'infile'.

Agree. When I'm in a hurry I let details slip.

>For the OP, you'll need 'c:\\input.txt' because the '\' has special meaning
>inside of a string so must be escaped.

Agree. When I'm in a hurry I let details slip.

> > fruits = {} # a dictionary to hold each fruit and its count
> > lines = input.readlines()
> > for line in lines:
>
>Since you are using Python 2.2 (later you use "if fruit in fruits",
>and "__in__" support for dicts wasn't added until Python 2.2, I
>think, and the 'file' usage is also new), this is best written as
>
>   for line in input:

Agree.

> >    fruit = line.split('_', 1)[0]
>
> >    if fruit in fruits:
> >      fruits[fruit] += 1 # increment count
> >    else:
> >      fruits[fruit] = 1 # add to dictionary with count of 1
>
>Here's a handy idiom for what you want
>
>       fruits[fruit] = fruits.get(fruit, 0) + 1

Don't you want setdefault() instead of get()?

> > output1 = file('c:\output1.txt', 'w')
> > for key, value in fruits.items():
> >    output1.write("%s occurs %s\n" % (key, value))
> > output1.close()
> > output2 = file('c:\output2.txt', 'w')
> > output2.write("Total occurrences is %s\n" % len(lines))
> > output2.close()
>
>That's missing some sorts, so I don't think it meets the OP's requirements.

The only reason for sort that I could see was to group things for counting. 
The output appears sorted descending, but that order was not specified, so 
I assumed random output.

[snip]

Bob Gailer
bgailer at alum.rpi.edu
303 442 2625
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