Why does ~True result in -2?

In Python console:


Gives me:


Why? Can someone explain this particular case to me in binary?

What is int(True)? It is 1.

1 is:


and ~1 is:


Which is -2 in Two's complement1

1 Flip all the bits, add 1 to the resulting number and interpret the result as a binary representation of the magnitude and add a negative sign (since the number begins with 1):

    11111110  00000001  00000010 
           Flip       Add 1

Which is 2, but the sign is negative since the MSB is 1.

Worth mentioning:

Think about bool, you'll find that it's numeric in nature - It has two values, True and False, and they are just "customized" versions of the integers 1 and 0 that only print themselves differently. They are subclasses of the integer type int.

So they behave exactly as 1 and 0, except that bool redefines str and repr to display them differently.

    >>> type(True)
    <class 'bool'>
    >>> isinstance(True, int)

    >>> True == 1
    >>> True is 1  # they're still different objects

From: stackoverflow.com/q/21881362

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