while True pattern in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an infinite loop using while.

Python

while [1]:
    print("Looping forever")

Drag options to blanks, or click blank then click option'

A0

BFalse

CNone

DTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using False or 0 as the condition, which stops the loop immediately.

Using None, which is not a boolean and causes an error.

The while True statement creates an infinite loop because the condition is always true.

2fill in blank

medium

Complete the code to break out of the infinite loop when user types 'exit'.

Python

while True:
    user_input = input("Type something: ")
    if user_input == [1]:
        break

Drag options to blanks, or click blank then click option'

A"quit"

B"exit"

C"stop"

D"end"

Attempts:

3 left

💡 Hint

Common Mistakes

Using words other than 'exit' which do not stop the loop.

Forgetting to put quotes around the string.

The loop breaks when the user types exit, so the condition must check for the string "exit".

3fill in blank

hard

Fix the error in the loop condition to make it an infinite loop.

Python

while [1] == True:
    print("Running")

Drag options to blanks, or click blank then click option'

ATrue

B1

CFalse

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using False or 0 which stops the loop.

Using 1 which works but is less clear than True.

The condition must be True to run infinitely. Using True == True is valid but redundant; just while True: is preferred.

4fill in blank

hard

Fill both blanks to create a loop that asks for a number and stops when the number is 0.

Python

while [1]:
    num = int(input("Enter number: "))
    if num [2] 0:
        break

Drag options to blanks, or click blank then click option'

ATrue

BFalse

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using while False which never runs the loop.

Using != which breaks on wrong condition.

The loop runs infinitely with while True: and breaks when num == 0.

5fill in blank

hard

Fill all three blanks to create a loop that asks for a password and stops when the correct password is entered.

Python

while [1]:
    pwd = input("Enter password: ")
    if pwd [2] [3]:
        break

Drag options to blanks, or click blank then click option'

ATrue

B==

C"secret123"

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using != which breaks on wrong password.

Forgetting quotes around the password string.

The loop runs forever with while True: and breaks when the password equals "secret123".

Practice

1.

What does the while True loop do in Python?

easy

A. It creates a loop that runs forever unless stopped by break.

B. It runs the loop only once.

C. It runs the loop a fixed number of times.

D. It causes a syntax error.

Solution

1. Step 1: Understand the meaning of while True

   The condition True is always true, so the loop will keep running forever.

2. Step 2: Recognize how to stop the loop

   To stop this infinite loop, a break statement is used inside the loop when a condition is met.

3. Final Answer:

   It creates a loop that runs forever unless stopped by break. -> Option A

4. Quick Check:

   while True = infinite loop until break [OK]

Hint: Remember: while True loops forever until break stops it [OK]

Common Mistakes:

• Thinking it runs only once
• Assuming it runs a fixed number of times
• Believing it causes a syntax error

2.

Which of the following is the correct syntax to stop a while True loop when a variable count reaches 5?

count = 0
while True:
    count += 1
    ?

easy

A. if count == 5: break

B. if count = 5: break

C. if count == 5: continue

D. if count > 5: stop

Solution

1. Step 1: Identify correct comparison operator

   Use == to compare values, so if count == 5 is correct.

2. Step 2: Use break to exit the loop

   The break statement stops the loop immediately when the condition is true.

3. Final Answer:

   if count == 5: break -> Option A

4. Quick Check:

   Use == and break to stop loop [OK]

Hint: Use double equals (==) for comparison and break to stop [OK]

Common Mistakes:

• Using single equals (=) instead of double equals (==)
• Using continue instead of break
• Using undefined commands like stop

3.

What will be the output of the following code?

i = 0
while True:
    i += 2
    if i > 6:
        break
print(i)

medium

A. 0

B. 6

C. 4

D. 8

Solution

1. Step 1: Trace the loop increments

   i starts at 0, then increases by 2 each loop: 2, 4, 6, 8.

2. Step 2: Check the break condition

   The loop breaks when i > 6, which happens when i becomes 8.

3. Final Answer:

   6 -> Option B

4. Quick Check:

   Loop stops at i=8 because 8 > 6, but the printed value is the last before break, which is 6 [OK]

Hint: Add increments step-by-step until break condition met [OK]

Common Mistakes:

• Stopping at i=6 instead of i=8
• Printing before break
• Confusing break condition with >= instead of >

4.

Find the error in this code snippet:

count = 0
while True
    count += 1
    if count == 3:
        break
print(count)

medium

A. Wrong comparison operator in if count == 3

B. Incorrect indentation of count += 1

C. Missing break statement

D. Missing colon after while True

Solution

1. Step 1: Check syntax of while statement

   Python requires a colon (:) after while True to start the loop block.

2. Step 2: Verify other parts

   Indentation and comparison operator are correct; break is present.

3. Final Answer:

   Missing colon after while True -> Option D

4. Quick Check:

   Loops need colon after condition [OK]

Hint: Look for missing colons after loop or if statements [OK]

Common Mistakes:

• Forgetting colon after while
• Misaligning indentation
• Confusing = and == in conditions

5.

You want to write a program that keeps asking the user to enter a number until they enter a negative number. Which code snippet correctly uses while True to do this?

hard

A. while num >= 0:
num = int(input('Enter number: '))
print(f'You entered {num}')

B. while True:
num = int(input('Enter number: '))
if num > 0:
break
print(f'You entered {num}')

C. while True:
num = int(input('Enter number: '))
if num < 0:
break
print(f'You entered {num}')

D. while True:
num = input('Enter number: ')
if num < 0:
break

Solution

1. Step 1: Check loop condition and input

   while True: num = int(input('Enter number: ')) if num < 0: break print(f'You entered {num}') uses while True and asks for input inside the loop, converting it to int.

2. Step 2: Verify break condition and output

   It breaks when the number is negative (< 0) and prints the number otherwise.

3. Final Answer:

   while True: num = int(input('Enter number: ')) if num < 0: break print(f'You entered {num}') -> Option C

4. Quick Check:

   Break on negative input inside infinite loop [OK]

Hint: Break loop when negative number entered, print otherwise [OK]

Common Mistakes:

• Breaking on wrong condition (positive instead of negative)
• Not converting input to int
• Missing print statement or break