009_While_Loop.md

While Loop

A while loop allows code to be repeated an unknown number of times as long as a condition is being met.

Code Examples

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# 9.0.1 A while loop
i = 1
while i < 6:
  print(i)
  i += 1

Comparison Operators

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• == Equal to and Both conditions must be met
• != Not equal to or Either condition must be met
• > Greater than
• < Less than
• >= Greater than or equal to
• <= Less than or equal to

# 9.0.2 Random Number 
import random
count=0
num = ''
rand = str(random.randint(1,10))

while num != rand:
    num = input("Enter a number between 1-10:" )
    count +=1

print(rand)
print(f"Guess Count {count}")
print("Correct!")

# 9.0.3 Break
import random
num = 1
while num > 0:
    print(num)
    num = random.randint(1,10)
    if num == 5:
        break
print("5 was found")

# 9.0.4 Else
i = 1
while i < 6:
  print(i)
  i += 1
else:
  print("Finished")

i = 1
while i < 10:
  print(i)
  i += 1

  if i == 8:
      break

else:
  print("Finished")

i = 1
while i < 10:
    print(i)

    i += 1

    if i == 4:
        continue
    else:
        print("next")

else:
    print("Finished")

009 Code Challenges

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Use the previous code examples to help you complete the code challenges

Challenge 1 - Counting

Write a while loop that adds all the numbers from 1 to 100

Challenge 2 - List Iteration

Take the following list:

numbers=[10, 99, 98, 85, 45, 59, 65, 66, 76, 12, 35, 13, 100, 80, 95]

Using a while loop iterate through the list and for every instance of 100 print out "Found one!"

Challenge 3 - Appending a list

Using the following list of names:

names=["Joe", "Sarah"]

Using a while loop allow users to add new names to the list indefinitely. Each time a user adds a new name ask the user if they would like to add another name. 1 = yes and 2 = no. The programme should stop if the users selects 2, no.

Challenge 4 - Dice Roll Simulator

Create a dice roll simulator whereby the user is first given an option on screen to either play or exit the simulator. An input() function is used to capture the users choice.

1. Roll the dice
2. Exit Game
Choose 1 or 2:

On the user selecting option 1, the simulator should produce a number between 1 and 6.

====
Dice Roll: 4
====

After which, the application should loop back to the introduction screen where the user is asked to choose option 1 or 2 once more. If the user selects option 2, the simulator should exit/stop.

1. Roll the dice
2. Exit Game
Choose 1 or 2:

Solutions

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# Challenge 1 - Counting
num = 1
while num <= 100:
    print(num)
    num +=1

# Challenge 2 - List Iteration
numbers=[100, 84, 68, 35, 42, 100, 65, 66, 76, 11, 35, 13, 100, 80, 95]
  
length = len(numbers)
i = 0
  
while i < length:

    if numbers[i] == 100:
        print("Found one!")

    i += 1

# Challenge 3 - Appending a list
names=["Joe", "Sarah"]
    
while True:

    names.append(input("Add a new name: "))
    print(names)
    x = int(input("Another name 1-yes 2-no: "))

    if x == 2:
        break

# Challenge 4 - Dice Roll Simulator
import random 
while True:     
     print("1. Roll the dice\n2. Exit Game")    
     user = int(input("Choose 1 or 2: "))     
     if user==1:         
        number = random.randint(1,6)         
        print(f"====\nDice Roll: {number}\n====")     
     else:      
        break