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# Python Truth Value Testing

## What is Truth Value

We can use any object to test the truth value. By providing the condition in the if or while statement, the checking can be done.

Until a class method __bool__() returns **False** or __len__() method returns 0, we can consider the truth value of that object is **True**.

The value of a constant is False, when it is

**False**, or**None**.When a variable contains different values like 0, 0.0, Fraction(0, 1), Decimal(0), 0j, then it signifies the False Value.

The empty sequence ‘‘, [], (), {}, set(0), range(0), Truth value of these elements are

**False**.

## Truth Value of 1 and 0

The truth value 0 is equivalent to False and 1 is same as True. Let’s see the truth value i.e. the truth value of 1 is True −

a = 1, then bool(a) = True

Let’s see the opposite of the truth value i.e. the truth value of 0 is False −

a = 0, then bool(a) = False

Let us see another quick example. The truth value of 1 is True −

a = 1 if(a==1) print(“True”)

The truth value of 0 is False −

a = 0 if(a==0) print(“False”)

## Python Truth Value Testing Example

Let us see a complete example −

### Example

class A: # The class A has no __bool__ method, so default value of it is True def __init__(self): print('This is class A') a_obj = A() if a_obj: print('It is True') else: print('It is False') class B: # The class B has __bool__ method, which is returning false value def __init__(self): print('This is class B') def __bool__(self): return False b_obj = B() if b_obj: print('It is True') else: print('It is False') myList = [] # No element is available, so it returns False if myList: print('It has some elements') else: print('It has no elements') mySet = (10, 47, 84, 15) # Some elements are available, so it returns True if mySet: print('It has some elements') else: print('It has no elements')

### Output

This is class A It is True This is class B It is False It has no elements It has some elements

- Related Questions & Answers
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- Automated software testing with Python
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