为什么集合中的 'True' 值元素有时会丢失?

Why 'True' value element inside a set is missing sometimes?

当 运行 下面的代码是集合练习时,我很困惑。集合名称 's' 中的元素包含布尔值 True。但是,它并不总是被识别或打印。详情请看评论。第二组's1'的情况并非如此。谁能告诉我这里出了什么问题。

这是代码:

s = {1,2,32,2,True,"Trial"}
s1 = { 5, False, True, 32}

print("s is : ", s)            # Element True is missing in the output
print("s1 is : ", s1)
print("Union : ",s.union(s1))  # Element True is missing in the output
print("Difference : ",s.difference(s1))
print("Intersection : ", s.intersection(s1)) # Element True is present in the output
print("Elements in s : ",*s)    # Element True is missing in the output of s
print("Elements in s1 : ",*s1)  # Element True is printed in the output of s1
if (True in s ) :
    print("True is truely in s")  
else:
    print("True not found in s")

if (False in s ) :
    print("False is truely in s")
else:
    print("Fasle not found in s")
for itm in s :
    print(itm, " : ", type(itm)) # Element True is missing in the output
# *** ??? the elemment True in s is printed only in the intersection

我得到的输出是这样的

s is :  {32, 1, 2, 'Trial'}
s1 is :  {False, True, 32, 5}
Union :  {32, 1, 2, False, 5, 'Trial'}
Difference :  {2, 'Trial'}
Intersection :  {32, True}
Elements in s :  32 1 2 Trial
Elements in s1 :  False True 32 5
True is truely in s
Fasle not found in s
32  :  <class 'int'>
1  :  <class 'int'>
2  :  <class 'int'>
Trial  :  <class 'str'>

[Done] exited with code=0 in 0.144 seconds

原因是(主要出于历史原因)Python 中的 True1 的一种同义词。所以 True1 具有相同的值,并且集合不能包含重复值。

>>> {1} == {True}
True
>>> len({1, True})
1
>>> True in {1}
True
>>> 1 in {True}
True

True 出现交集是因为您看到的值 1 的表示取决于表达式的求值顺序。

>>> s.intersection(s1)
{32, True}
>>> s1.intersection(s)
{32, 1}

如果您尝试创建具有两个值 0False 的集合(结果 {0}{False} 取决于表达式的顺序)或具有两个值 11.0 的集合(结果 {1}{1.0} 取决于表达式的顺序)。