In this article, we are going to learn about python bool() function with examples.

Getting Started

Python bool() function is used to convert any value into boolean value i.e. True or False.

Syntax of bool() Function

Syntax of bool() in python is –

 
bool(value)

Where,
value is argument passed to bool() function.

Parameter of bool() Function

bool() function accepts one parameter –

• value: It’s boolean value is returned.

If no parameter is passed, by default bool() returns False.

Return Value of bool() Function

Python bool() function returns boolean value. So, it’s either True or False.

• True: If argument, value, is any number (except 0) or string.
• False: Few cases where bool() function returns false –
  • If a False value is passed.
  • If None is passed.
  • If an empty sequence is passed e.g. Empty set – (), Empty List – [], Empty Mapping – {} etc.
  • If 0 is passed e.g. 0, 0.0 etc.
  • If object of Class which have bool() or len() function returns 0 or False

Examples of bool() Function

Now, let’s see some examples of bool() function –

• Example 1: False value as argument

  In this example, we will see some of possible cases where bool() function is accepting value that is considered as False on Truth Testing Procedure.

   
  # Examples of built-in function bool()
  # that returns False value
  
  # Output: False
  y = False
  print(bool(y))
  
  # x is not equal to y. So, False
  x = 5
  y = 10
  print(bool(x == y))
   
  # Output: False
  y = None
  print(bool(y))
   
  # Output: False
  y = ()
  print(bool(y))
   
  # Output: False
  y = {}
  print(bool(y))
   
  # Output: False
  y = 0.0
  print(bool(y))
  
  

  Output:

   
  False
  False
  False
  False
  False
  False
  

  As discussed above, we get False as output in all cases.

• Example 2: True value as argument

   
  # Examples of built-in function bool()
  # that returns True value
  
  # Output: False
  y = True
  print(bool(y))
  
  # x is not equal to y. So, False
  x = 10
  y = 10
  print(bool(x == y))
   
  
  # Output: False
  y = (1,2,)
  print(bool(y))
   
  # Output: False
  y = {'1': "Hello"}
  print(bool(y))
   
  # Output: False
  y = 1.0
  print(bool(y))
  

  Output:

   
  True
  True
  True
  True
  True
  

  As discussed above, bool() function returns True in all cases.

Learn more at official doc.

That’s end of our post on python bool() function with examples.