代码中经常会有变量是否为None的判断,有三种主要的写法: 第一种是`if x is None`: 第二种是 `if not x:`: 第三种是`if not x is None`(这句这样理解更清晰`if not (x is None)`) . `if x is not None`是最好的写法,清晰,不会出现错误,以后坚持使用这种写法. 使用if not x这种写法的前提是:必须清楚x等于None, False, 空字符串"", 0, 空列表[], 空字典{}, 空元组()时对你的
a_ip:10.10.15.100b_ip:10.10.15.101c_ip:10.10.10.100netmask:255.255.255.0 def numtobinary(num): binary = '' a = int(num) while 1: if a == 0 or a == 1: binary = '%s%s' % (str(a), binary) break num = a % 2 binary = '%s%s' % (str(num), binary) a = a / 2
def common_data(list1, list2): result = False for x in list1: for y in list2: if x == y: result = True return result print(common_data([,,,,], [,,,,])) print(common_data([,,,,], [,,,]))