19.4: Boolean Functions
- Page ID
- 15386
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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.
Exercise \(\PageIndex{1}\)
Write a function is_between(x, y, z) that returns True if x ≤ y ≤ z or False otherwise