python在后面每一行后面加一个冒号或其他内容

处理签文件

代码

lines = []
with open('id.txt', 'r') as f_in:
    for line in f_in:
        line = line[0:-1] + ':' + '\n'
        lines.append(line)

with open('id_.txt', 'w') as f_out:
    f_out.writelines(lines)

　处理后文件内容