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# Truthy vs Falsy Values in Python

• Difficulty Level : Basic
• Last Updated : 05 Sep, 2020

In this article, we will see about the concept of Truthy and Falsy values in Python and also see how to determine a value is Truthy or Falsy by using bool() built-in Python function.

## Python3

 `number ``=` `7``if` `number:``  ``print``(number)`

Output:

```7

```

Let’s change value of number to 0

## Python3

 `number ``=` `0``if` `number:``  ``print``(number)`

Output:

```There is no Output

```

Have you wondered why the above code run successfully despite number not being an expression?

The answer lies in concept of Truthy and Falsy Values.

## Truthy vs Falsy Values

In Python, individual values can evaluate to either True or False.

The Basis rules are:

• Values that evaluate to False are considered Falsy.
• Values that evaluate to True are considered Truthy.

Falsy Values Includes:

1) Sequences and Collections:

• Empty lists []
• Empty tuples ()
• Empty dictionaries {}
• Empty sets set()
• Empty strings ” “
• Empty ranges range(0)

2) Numbers: Zero of any numeric type.

• Integer: 0
• Float: 0.0
• Complex: 0j

3) Constants:

• None
• False

Falsy values were the reason why there was no output in our initial example when the value of number was zero.

Truthy Values Includes:

• Non-empty sequences or collections (lists, tuples, strings, dictionaries, sets).
• Numeric values that are not zero.
• Constant: True

This is why the value of a printed in our initial example because its value of a number was 7(a truthy value):

## Built-in bool() function

You can check if a value is either truthy or falsy with the built-in bool() function. This function is used to return or convert a value to a Boolean value i.e., True or False, using the standard truth testing procedure

Syntax: bool(parameter)

You only need to pass the value as an argument.

Example:

## Python3

 `bool``(``7``)``# True`` ` `bool``(``0``)`` ``#False``   ` `bool``([])``# False`` ` `bool``({``7``,``4``})``#True`` ` `bool``(``-``4``)``# True`` ` `bool``(``0.0``)``# False`` ` `bool``(``None``)``# False`` ` `bool``(``1``)``#True`` ` `bool``(``range``(``0``))``# False`` ` `bool``(``set``())``# False`` ` `bool``([``1``,``2``,``3``,``4``])``# True`

Output:

```True
False
False
True
True
False
False
True
False
False
True

```

Now let’s see a program for better understanding of Truthy and Falsy value.

Example:

## Python3

 `# define a function for checking``# number is even or odd``def` `even_odd(number):``   ` `  ``if` `number ``%` `2``: ``     ` `     ``# since num % 2 is equal to 1``     ``# which is Truthy Value``     ``return` `'odd number'``     ` `  ``else``: ``     ` `     ``# since num%2 is equal to 0``     ``# which is Falsy Value.``     ``return` `'even number'`` ` `result1 ``=` `even_odd(``7``)`` ` `# prints odd``print``(result1) `` ` `result2 ``=` `even_odd(``4``)`` ` `# prints even``print``(result2) `

Output:

```odd number
even number

```

Since in first function call num % 2 is equal to 1 which is Truthy Value, so output is ‘odd number’ and in second function call num % 2 is equal to 0 which Falsy Value, so output is ‘even number’.

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