Python - Booleans

Python Booleans (bool)

In Python, bool is a sub-type of int type. A bool object has two possible values, and it is initialized with Python keywords, True and False.

Example

>>> a=True
>>> b=False
>>> type(a), type(b)
(<class 'bool'>, <class 'bool'>)

A bool object is accepted as argument to type conversion functions. With True as argument, the int() function returns 1, float() returns 1.0; whereas for False, they return 0 and 0.0 respectively. We have a one argument version of complex() function.

If the argument is a complex object, it is taken as real part, setting the imaginary coefficient to 0.

Example

a=int(True)
print ("bool to int:", a)
a=float(False)
print ("bool to float:", a)
a=complex(True)
print ("bool to complex:", a)

On running this code, you will get the following output −

bool to int: 1
bool to float: 0.0
bool to complex: (1+0j)

Python Boolean Expression

Python boolean expression is an expression that evaluates to a Boolean value. It almost always involves a comparison operator. In the below example we will see how the comparison operators can give us the Boolean values. The bool() method is used to return the truth value of an expresison.

Syntax: bool([x])
Returns True if X evaluates to true else false.
Without parameters it returns false.

Below we have examples which use numbers streams and Boolean values as parameters to the bool function. The results come out as true or false depending on the parameter.

Example

# Check true
a = True
print(bool(a))
# Check false
a = False
print(bool(a))
# Check 0
a = 0.0
print(bool(a))
# Check 1
a = 1.0
print(bool(a))
# Check Equality
a = 5
b = 10
print(bool( a==b))
# Check None
a = None
print(bool(a))
# Check an empty sequence
a = ()
print(bool(a))
# Check an emtpty mapping
a = {}
print(bool(a))
# Check a non empty string
a = 'Tutorialspoint'
print(bool(a))