摘要:
is 和 == 的区别 is 对比的是地址 == 对比值 判空的常见规则 对于可变数据结构(list dict set) l = [] if l: print('true') 对于不可变数据,一般使用 == 对于 None,总是使用 is >>> a = [] >>> b = [] >>> id(a 阅读全文
摘要:
Popen is nonblocking. call and check_call are blocking. You can make the Popen instance block by calling its wait or communicate method. If you look i 阅读全文