# 19.4: Boolean Functions

- Page ID
- 15386

Functions can return booleans, which is often convenient for hiding complicated tests inside functions. For example:

def is_divisible(x, y): if x % y == 0: return True else: return False

It is common to give boolean functions names that sound like yes/no questions; `is_divisible`

returns either `True`

or `False`

to indicate whether `x`

is divisible by `y`

.

Here is an example:

>>> is_divisible(6, 4) False >>> is_divisible(6, 3) True

The result of the `==`

operator is a boolean, so we can write the function more concisely by returning it directly:

def is_divisible(x, y): return x % y == 0

Boolean functions are often used in conditional statements:

if is_divisible(x, y): print 'x is divisible by y'

It might be tempting to write something like:

if is_divisible(x, y) == True: print 'x is divisible by y'

But the extra comparison is unnecessary.

Exercise \(\PageIndex{1}\)

*Write a function is_between(x, y, z) that returns *

`True`

*if*

*x*≤*y*≤*z*or`False`

*otherwise*