Returning Multiple Values¶
It is possible for a Python function to return multiple values. To To accomplish this, we can combine the desired return values together into a list or a tuple, which we then return. Alternately, we can simply list the return values in the return statement, separated by commas.
When storing the values returned by such a function in variables, we can list the target variable names on the left of the assignment operator, separated by commas.
def power(a,b):
return (a**b, b**a)
a_to_b, b_to_a = power(2,5)
print(a_to_b)
print(b_to_a)
32
25
Example: Division with Remainder¶
Write a function div_w_remainder() that takes two arguments, num and div, and returns the number of times that div evenly divides num (i.e. the quotient), as well as the remainder of num after division by div. Coerce the remainder into an integer.
def div_w_remainder(num, div):
quotient = int(num/div)
remainder = num % div
return (quotient, remainder)
We will now consider several examples to test our function.
q, r = div_w_remainder(17, 3)
print('Quotient: ', q)
print('Remainder:', r)
Quotient: 5
Remainder: 2
q, r = div_w_remainder(459, 17)
print('Quotient: ', q)
print('Remainder:', r)
Quotient: 27
Remainder: 0
q, r = div_w_remainder(6237, 13)
print('Quotient: ', q)
print('Remainder:', r)
Quotient: 479
Remainder: 10
Example: Locating Elements in a List¶
Write a function called locate. The function should take two arguments: a list called x, and another variable called item.
The function should return two values: A list of indices at which the element in x is equal to item, and a count of the number of times that item appears in x.
def locate(x, item):
index_list = []
for i in range(0, len(x)):
if x[i] == item:
index_list.append(i)
return (index_list, len(index_list))
A list of student grades is provided in the cell below. Call locate() five times. In each function call, pass in grades for x. For item, use each of the following values: 'A', 'B', 'C', 'D', and 'F'.
For each function call, print out a message of the following form:
A: indices = [......], count = ##
grades = ['A', 'D', 'A', 'C', 'B', 'F', 'A', 'D', 'C', 'B', 'F', 'A', 'C',
'B', 'A', 'B', 'B', 'C', 'B', 'F', 'D', 'D', 'A', 'C', 'B']
for letter in ['A', 'B', 'C', 'D', 'F']:
idx, c = locate(grades, letter)
print(str(letter) + ': indices = ' + str(idx) + ', count = ' + str(c) )
A: indices = [0, 2, 6, 11, 14, 22], count = 6
B: indices = [4, 9, 13, 15, 16, 18, 24], count = 7
C: indices = [3, 8, 12, 17, 23], count = 5
D: indices = [1, 7, 20, 21], count = 4
F: indices = [5, 10, 19], count = 3