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 6.3.Write a function is_between(x, y, z)that returns Trueif x ≤ y ≤ z or False otherwise.