在python中对包含字符串和数字的txt文件进行排序

Question

I want to sort a txt file containing both strings and numbers by ascending numbers. example of a file:

Berlin 400

London 903

Oslo 905

Washington 300

So for example I want this file to be sorted by ascending number, like this:

Washington 300

Berlin 400

London 903

Oslo 905

How do I do this?

Answer 1

Say you have a file capitals.txt with the following contents:

Berlin 400
London 903
Oslo 905
Washington 300

You could consider parsing the data into a list of namedtuples before sorting and writing the list to an output file:

from collections import namedtuple

CapitalInfo = namedtuple('CapitalInfo', 'name num')

capitals = []
with open('capitals.txt', 'r') as capitals_file:
    for row in capitals_file:
        name, num_str = row.split()
        num = int(num_str)
        capitals.append(CapitalInfo(name, num))

capitals.sort(key=lambda c: (c.num, c.name))

with open('sorted_capitals.txt', 'w') as sorted_capitals_file:
    for name, num in capitals[:-1]:
        sorted_capitals_file.write(f'{name} {num}\n')
    name, num = capitals[-1]
    sorted_capitals_file.write(f'{name} {num}')

What sorted_capitals.txt contents are after running above:

Washington 300
Berlin 400
London 903
Oslo 905

Try it here .