python 按多维列表中的某一个元素位进行排序

import os,re

top = os.popen("tasklist")

process_list = []

split_r = r"\s+"

memory_topTen = []

for key,item in enumerate(top):
    item = str(item).rstrip("\n")

    if  key not in [0,1,2]:
        result = re.split(split_r,item)
        if len(result)== 6:
            memory_topTen.append(result)

# print(memory_topTen)

#  获取列表第5个元素
def takeSecond(elem):
    return elem[4]

memory_topTen.sort(key= takeSecond,reverse=True)

memory_topTen = memory_topTen[0:10]

for item in memory_topTen:
    print(item)