文件处理，

修改文件，

#! /usr/bin/env python

f = open('lyst',"r",encoding="utf-8")
f_new = open('lyst.bak',"w",encoding="utf-8")

for line in f:
    if "So many wild" in line:
        line = line.replace("So many wild","so many kids")
    f_new.write(line)
f.close()
f_new.close()

 打开文件，

with open('lyst','r',encoding="utf-8") as f:
    for line in f:
        print(line.strip())