Challenge - 05 - while Loops#

1. Write a while loop such that you print out the first 10 natural numbers:#

1

2

3

4

5

6

7

8

9

10

# variable declarations?

# while

2. Write a while loop that prints the following even numbers:#

2

4

6

8

10

12

14

16

18

20

# variables?

# while ...

3. Write a while loop that processes all the lower-case letters and prints out a letter if it is a vowel#

Preliminaries to writing the loop#

A handy operator in Python is in which returns a boolean answering whether some item is present in an interable such as a string. For example:

some_characters = 'abcdefg'
# use 'in' to see if an 'e' is present

print('x' in some_characters) # will return and print 'False'
print('e' in some_characters) # will return and print 'True'

False
True

Use in to write the loop.

Additional hints:

  1. use an if statement in the loop

  2. The if statement should check if a character is in the string vowels.

  3. If it is, use a print statement to output it.

Note: Make sure to remove the pass keyword

letters = 'abcdefghijklmnopqrstuvwxyz'
vowels = 'aeiou'

count = 0
while count < len(letters):
    # do something here
    count += 1

4. Write a while loop that generates a random integer from 1000 to 1100 and only breaks out if the integer is equal to 1050 but not before printing out the 1050!#

from random import randint

while True:
    pass

5. Countdown#

  • Write a procedure named countdown()

  • It should take in an integer and prints backward from that integer down to 0 and then prints “Blastoff!”

  • Call it with the integer 10


def countdown(i):

    while i >= 0:
        pass

countdown(10)