摘要：实例1 import threading #线程 import time def Hi(num): print("线程总用时：%d sec --> start "%num) time.sleep(num) #等待时间 print("线程结束%d" % num) if __name__ == '__m 阅读全文

摘要：****************************************with语句******************************************* with expression as target: with-body import os,sys os.chdir( 阅读全文