is和equals(==)运算符大致相同,但不相同。is运算符定义两个变量是否都指向同一对象,而==符号检查两个变量的值是否相同。
# Python program to
# illustrate the
# difference between
# == and is operator
# [] is an empty list
list1 = []
list2 = []
list3=list1
if (list1 == list2):
print("True")
else:
print("False")
if (list1 is list2):
print("True")
else:
print("False")
if (list1 is list3):
print("True")
else:
print("False")输出结果
True False True