Python根据列值从最高到最低对文本文件进行排序

Question

I have a very large text file that contains lines of data like:

('#DownWithAssad', '1')
('#DownYoTLParty', '1')
('#Download', '8')
('#Download:', '2')
('#Downloads', '2')
('#DownstairsMixtape', '1')
('#DowntonAbbey', '12')
('#DowntonAbbey?', '1')
('#DowntonPBS', '23')
('#Downtonabbey', '1')
('#DowntownAbbey', '1')

This may seem like a simple problem but I want to soft the data from highest to lowest so it looks like:

('#DowntonPBS', '23')
('#DowntonAbbey', '12')
('#Download', '8')
('#Download:', '2')
('#Downloads', '2')
('#DownstairsMixtape', '1')
('#DownWithAssad', '1')
('#DownYoTLParty', '1')
('#DowntonAbbey?', '1')
('#Downtonabbey', '1')
('#DowntownAbbey', '1')

I gather that I can eliminate the brackets () and split the data with:

import sys

f = open(sys.argv[1])
for line in f:
    line = str(line)[1 : -1]
    for sect in line.split(','):
        print sect

However I'm not sure where to go from here.

Answer 1

You can parse your text file quite easily using ast.literal_eval :

with open(datafile) as f:
    file_sorted = sorted((ast.literal_eval(x) for x in f),
                         key=lambda z:(int(z[1]),z[0]),
                         reverse=True)

How it works:

(ast.literal_eval(x) for x in f)  #turn each line in your file into a tuple
key=lambda z:(int(z[1]),z[0])     #function to determine how things are sorted.  Basically
                                  #sort as tuples:  `( int(z[1]),z[0] )`
reverse=True                      #descending order instead of ascending

Answer 2

This is along the lines of what you are trying to do. Note that parsing the lines this way is quite fragile (misformatted lines may break it)

from operator import itemgetter
import sys

result=[]
with open(sys.argv[1]) as f:
    for line in f:
        line = str(line.strip())[1: -1]
        sect1, sect2 = line.split(', ')
        sect1 = sect1[1: -1]
        sect2 = int(sect2[1: -1])
        result.append((sect1, sect2))

for line in sorted(result, key=itemgetter(1), reverse=True):
    print line

Better ways to parse it would be to use literal_eval or regular expressions. Do you know if there is any special treatment when quote characters or commas appear in the strings?