Exercises for Lesson 8
Exercise 1: Multi-way decisions
For each of the following code snippets, predict what will be printed.
x = 5
y = 10
# (a)
if y % x == 0:
print("yeppers")
elif y > 3:
print("so true")
else:
print("maybe not")
# (b)
if x < y:
print("cheddar")
elif y != x:
print("mal")
# (c)
if x < y:
print("cheddar")
if y != x:
print("mal")
# (d)
if x == 4:
print("four")
elif x == 5:
print("five")
elif y == 8:
print("eight")
elif y == 10:
print("ten")
elif y == 12:
print("twelve")
else:
print("nada")Exercise 2: Conditionals in loops
Part a: Contains 0
Write a function containsZero that returns True if the provided list contains the number 0 and False otherwise.
def containsZero(numList):
"""
Returns True if the list contains 0 as an element and False otherwise.
numList: a list of numbers (each is an int)
returns: a Boolean (True or False)
"""
pass # replace with your codePart b: Find negative
Write a function findNegative that returns the index of the first negative number in the provided list, or -1 if the list contains only non-negative numbers.
def findNegative(numList):
"""
Returns the index of the first negative number in the list, or -1 if not found.
numList: a list of numbers (ints or floats)
returns: the index of the first negative number or -1 (int)
"""
return -1 # replace with your codeExercise 3: Count evens
Extend our countEvens function to find the count of even numbers in a list.
def countEvensList(numList):
"""
Returns the number of even numbers in the given list.
Assumes the list contains only numbers.
"""
pass # replace with your codeExercise 4: More practice with conditionals
Part a: use a for loop
Further extend your countEvensList function to ask the user for numbers instead of taking in a list.
def countEvensN():
"""
Asks the user for a series of numbers and returns the count of even numbers.
Returns: the count of even numbers the user enters
"""
pass # replace with your codeAsk the user for n and then ask for each of the n values in a for loop.
Part b: use a while loop
Read ahead about while loops in Zelle sections 7.1–7.3 (pp. 199–208).
Then, change your countEvensN function to instead ask the user to enter numbers one at a time (rather than entering n first) or to enter nothing (just press enter, giving an empty string "") to quit.