51.Python：sys模块

import sys
import time


# sys.argv            # 命令行参数list，第一个元素是程序本身路径
# sys.exit()          # 退出程序


# 打印进度条
def progress(percent):
    res = '#' * int(percent * 50)
    print('\r[%-50s] %d%%' % (res, percent*100), end='')


w_percent = 0
recv_size = 0
total_size = 100

while recv_size < total_size:
    recv_size += 1
    time.sleep(0.2)
    w_percent = recv_size / total_size
    if w_percent > 1:
        w_percent = 1
    progress(w_percent)