Boolean "True" is not printing from set in Python-CodePudding

c= {1,3,5,89.07, True, "Night", 1,3}
print(c)

when I run this code, the output I received was, {1, 3, 'Night', 5, 89.07}

but when I replaced the "True" bool with False, the output was, {False,1, 3, 'Night', 5, 89.07}

So, why it is not giving "True" bool in first case ?

CodePudding user response：

Note that a similar effect is observed for 0:

>>> print({ 1, True })
{1}
>>> print({ 0, False })
{0}

This seems to be because in Python bool is a subclass of int, and often False acts like 0 and True like 1:

>>> isinstance(True, int)
True
>>> False   True
1
>>> False * 100
0
>>> 8 ** False
1

It's even the case that False == 0 and True == 1!

So in your case because 1 is already in your set, adding True to it makes no difference. But if you add False you get a new element.

CodePudding user response：

It is because sets return UNIQUE values only. In python, True corresponds to 1 and False to 0. Therefore:

c = {0,False}                                                                                                                                                     
print(c)                                                                                                                                                              
# {0}                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
c = {1, False}                                                                                                                                                        
print(c)                                                                                                                                                           
#{False, 1}                                                                                                                                                                
c = {0, True}                                                                                                                                                         
print(c)                                                                                                                                                              
#{0, True}