Python Loop Quiz

What is a for loop used for in Python?

• To execute a block of code indefinitely

• To iterate over a sequence

• To evaluate conditions only

• To terminate a program

Answer explanation

A for loop in Python is specifically designed to iterate over a sequence, such as a list, tuple, or string, allowing you to execute a block of code for each item in that sequence.

What is the output of the following code? python Copy code for i in range(3): print(i)

• 1 2 3

• 0 1 2

• 0 1 2 3

• None

Answer explanation

The code uses a for loop with range(3), which generates numbers starting from 0 up to, but not including, 3. Therefore, the output will be 0, 1, and 2, making the correct answer '0 1 2'.

What keyword is used to stop a while loop in Python?

• exit

• stop

• break

• continue

Answer explanation

In Python, the keyword 'break' is used to exit a while loop prematurely. The other options, 'exit', 'stop', and 'continue', do not serve this purpose. 'Continue' actually skips to the next iteration of the loop.

How many times will this loop run? python Copy code count = 0 while count < 5: count += 1

• 4

• 5

• Infinite

• 6

Answer explanation

The loop starts with count = 0 and increments count by 1 each iteration. It runs while count is less than 5. Therefore, it will run 5 times (count = 1 to 5) before exiting, making the correct answer 5.

What does range(5) generate?

• 1 to 5

• 0 to 5

• 0 to 4

• Infinite values

Answer explanation

The function range(5) generates a sequence of numbers starting from 0 up to, but not including, 5. Therefore, it produces the values 0, 1, 2, 3, and 4, making the correct answer 0 to 4.

What does the continue keyword do in a loop?

• Stops the loop completely

• Skips the current iteration and continues to the next

• Repeats the current iteration

• Breaks the loop

Answer explanation

The continue keyword in a loop skips the current iteration when encountered and proceeds to the next iteration. This allows the loop to continue running without executing the remaining code in the current iteration.

What will this code output? python Copy code for i in range(4): if i == 2: continue print(i)

• 0 1 2 3

• 0 1 3

• 1 3

• None

Answer explanation

The loop iterates from 0 to 3. When i is 2, the 'continue' statement skips the print. Thus, the output is 0, 1, and 3, making the correct answer '0 1 3'.

Which loop is best for iterating over a list?

• for loop

• while loop

• Both are equally suitable

• Neither

Answer explanation

The for loop is best for iterating over a list because it is specifically designed for this purpose, providing a clear and concise syntax. While a while loop can also be used, it is less straightforward and can lead to errors if not managed properly.

What does this code do? python Copy code while True: print("Hello")

• Prints "Hello" once

• Prints "Hello" 5 times

• Runs infinitely printing "Hello"

• Raises an error

Answer explanation

The code creates an infinite loop using 'while True:', which continuously executes the print statement. Therefore, it runs infinitely printing 'Hello' without stopping.

What is the correct way to write an infinite loop?

• for i in range():

• while True:

• while False:

• for i == True:

Answer explanation

The correct way to write an infinite loop is 'while True:'. This creates a loop that will continue indefinitely since the condition 'True' is always satisfied. The other options do not create infinite loops.