6.4: Boolean functions
- Page ID
- 40888
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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.
As an exercise, write a function is_between(x, y, z)
that returns True
if \( x \leq y \leq z \) or False
otherwise.