python 检查列表是否为空

is not None 判断

列表不为空

list_1 = []
if list_1 is not None:
    print('list is not none')

列表为空

list_1 = []
if list_1[0] is None:
    print('list_1 is none')

if 列表判断

列表不为空（空列表等于 False）

list_2 = []
if list_2:
    print('list_2 is not none')

length列表长度判断

列表为空

list_3 = []
if len(list_3) == 0:
    print('list_3 is none')

list_3 = []
if len(list):
    print('list_3 is not none')