读取TXT文件，排序后写回原TXT文件（含附件）

import numpy as np

nums=[]

f = open("5.txt", "r+")
index = -1
while True:
    x = f.readline()
    if len(x) == 0 : break
    if x[0].isnumeric():            
        nums.append(x)
        if index == -1:
            index = f.tell()-len(x)-1

nums=np.sort(nums)

f.seek(index)
f.writelines(nums)
f.close()