Python built-in bool functions

This article introduces the Python built-in bool function in detail.

English document:

Classbool([X])

Return a Boolean value, I. e. oneTrueOrFalse.XIs converted using the standard truth testing procedure. IfXIs false or omitted, this returnsFalse; Otherwise it returnsTrue.boolClass is a subclassint(See Numeric Types-int, float, complex). It cannot be subclassed further. Its only instances areFalseAndTrue(See Boolean Values ).

Note:

1. Boolean values that return True or False

2. if the parameter is set to the default value, False is returned.

>>> Bool () # unspecified parameter False

3. Use a standard logical test expression for parameter conversion

3.1 When a Boolean type is passed in, the return value is based on the original value.

>>> bool(True)True>>> bool(False)False

3.2 if a null string is input, False is returned; otherwise, True is returned.

>>> bool('')False>>> bool('0')True

3.3 when a value is input, False is returned for the value 0; otherwise, True is returned.

>>> bool(0)False>>> bool(1)True>>> bool(-1.0)True

3.4 if the number of elements is null when objects such as tuples, lists, and dictionaries are input, False is returned; otherwise, True is returned.

>>> Bool () # empty tuples False >>> bool (0,) # Non-empty tuples True >>> bool ([]) # Empty list False >>> bool ([0]) # Non-empty list True >>> bool ({}) # empty dictionary False >>> bool ({'K ': 'V'}) # Non-empty dictionary True

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