在文件每行文字的末尾加上特定字符

版权声明：笔记而已 https://blog.csdn.net/whalefall/article/details/86648516

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

with open('C://zl/test.txt', 'w') as f_out:
    f_out.writelines(lines)