Python Booleans

Vipin | Sun, 14 Jun, 2020 | 208

Python Booleans

Booleans represent one of two values: True or False.

Boolean Values

In programming you often need to know if an expression is True or False.

You can evaluate any expression in Python, and get one of two answers, True or False.

When you compare two values, the expression is evaluated and Python returns the Boolean value.

Example:-

print(10 > 9) # True
print(10 == 9) # True
print(10 < 9) # False

When you run a condition in an if statement, Python returns True or False.

Example:-

a = 500
b = 332

if b > a:
  print("b is greater than a")
else:
  print("b is not greater than a")

Evaluating Boolean Values and Variables

The bool() function allows you to evaluate any value, and give you True or False in return.

print(bool(15)) # True
print(bool("Hello")) # True

x = "Hello"
y = 15

print(bool(x))  # True
print(bool(y))  # True

True Values In Returned from Bool ()

Almost any value is evaluated to True if it has some sort of content.

Any string is True, except empty strings.

Any number is True, except 0.

Any list, tuple, set, and dictionary are True, except empty ones.

Example:-

The following will return True:

bool("abc")
bool(123)
bool(["apple", "cherry", "banana"])

False Values In Returned from Bool ()

In fact, there are not many values that evaluates to False, except empty values, such as ()[]{}"", the number 0, and the value None. And of course the value False evaluates to False.

Example:-

The following will return False:

bool(False)
bool(None)
bool(0)
bool("")
bool(())
bool([])
bool({})

Returning Boolean Value from Functions

Function can also returned boolean values.

Examples:-

def function(a,b):
    if a == b:
       return True
    else:
       return False

value = function(10,20)
print(value)  # False
value = function(10,10)
print(value1) # True

 

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