code。f = open(&#39；yesterday&#39；，&#39；r&#39；，encoding=&#39；utf-8&#39；)f2 = open(&#39；yesterday.bak&#39；，&#39；w&#39；，encoding=&#39；utf-8&#39；)old_str = input(&#39；请输入要修改的字符：&#39；)replace_str = input(&#39；请输入替换成的字符：&#39；)for line in f.readlines()： line = line.replace(old_str，replace_str) print(line) f2.write(line)f.close()f2.close()。