python 判断数组、字符串、对象、字典等是否为空？
字符串为空判断
phone = None
if phone:
print('true')
else:
print('false')
phone = ""
if not phone:
print('false')
else:
print('true')
打印
false
false
其他常量判断 同理字符串
phone = {}
phone = None
phone = ""
phone = []
phone = 0
这些都是false
