Why loop control is required in Python - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print numbers from 1 to 5 using a loop.

Python

for i in range(1, [1]):
    print(i)

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

A6

B5

C10

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 5 as stop will print 1 to 4 only.

The range function stops before the end number, so to print 1 to 5, we use 6 as the stop.

2fill in blank

medium

Complete the code to stop the loop when i equals 3.

Python

for i in range(1, 6):
    if i == [1]:
        break
    print(i)

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

A1

B5

C3

D6

Attempts:

3 left

💡 Hint

Common Mistakes

Using break with wrong value stops loop too early or too late.

The break stops the loop when i is 3, so numbers 1 and 2 print only.

3fill in blank

hard

Fix the error in the loop to skip printing number 3.

Python

for i in range(1, 6):
    if i == [1]:
        continue
    print(i)

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

A3

B2

C5

D4

Attempts:

3 left

💡 Hint

Common Mistakes

Using continue with wrong value skips wrong number.

The continue skips the current loop when i is 3, so 3 is not printed.

4fill in blank

hard

Fill both blanks to create a dictionary of squares for numbers greater than 2.

Python

squares = {x: x[1]2 for x in range(1, 6) if x [2] 2}

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

A**

B+

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using + instead of ** changes meaning.

Using < instead of > filters wrong numbers.

Use ** to square numbers and > to filter numbers greater than 2.

5fill in blank

hard

Fill all three blanks to create a dictionary with uppercase keys and values greater than 0.

Python

result = [1]: [2] for k, v in data.items() if v [3] 0}

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

Ak.upper()

Bv

C>

Dk

Attempts:

3 left

💡 Hint

Common Mistakes

Using k instead of k.upper() keeps keys lowercase.

Using < instead of > filters wrong values.

Keys are converted to uppercase with k.upper(), values are v, and filter keeps values greater than 0.

Practice

1. Why is loop control important in programming loops?

easy

A. To stop loops when a condition is met and avoid infinite loops

B. To make loops run slower

C. To increase the number of loop iterations automatically

D. To print output inside the loop

Solution

1. Step 1: Understand loop control purpose

   Loop control statements like break help stop loops early when needed.

2. Step 2: Recognize infinite loop prevention

   Without loop control, loops might run forever, causing the program to freeze.

3. Final Answer:

   To stop loops when a condition is met and avoid infinite loops -> Option A

4. Quick Check:

   Loop control prevents infinite loops [OK]

Hint: Loop control stops or skips to manage loops safely [OK]

Common Mistakes:

• Thinking loop control makes loops slower
• Believing loop control increases iterations
• Confusing loop control with printing output

2. Which of the following is the correct syntax to stop a loop early in Python?

easy

A. break

B. exit

C. stop

D. skip

Solution

1. Step 1: Recall Python loop control keywords

   Python uses break to stop loops early.

2. Step 2: Identify correct keyword

   Other options like stop, exit, and skip are not valid loop control keywords.

3. Final Answer:

   break -> Option A

4. Quick Check:

   Stop loop early keyword = break [OK]

Hint: Remember: 'break' stops loops immediately [OK]

Common Mistakes:

• Using 'stop' or 'exit' instead of 'break'
• Confusing 'continue' with stopping the loop
• Misspelling 'break'

3. What will be the output of this code?

for i in range(5):
    if i == 3:
        break
    print(i)

medium

A. 3 4

B. 0 1 2 3 4

C. 0 1 2

D. 0 1 2 3

Solution

1. Step 1: Analyze loop iterations and break condition

   The loop runs from 0 to 4, but breaks when i == 3.

2. Step 2: Determine printed values before break

   Values 0, 1, 2 are printed; loop stops before printing 3.

3. Final Answer:

   0 1 2 -> Option C

4. Quick Check:

   Loop breaks at 3, prints before break = 0 1 2 [OK]

Hint: Break stops loop before printing the break value [OK]

Common Mistakes:

• Including 3 in output
• Printing all numbers ignoring break
• Confusing break with continue

4. Find the error in this code that tries to skip printing number 2:

for i in range(4):
    if i = 2:
        continue
    print(i)

medium

A. Missing colon after if statement

B. Using '=' instead of '==' in if condition

C. continue cannot be used in loops

D. range(4) is incorrect

Solution

1. Step 1: Check if condition syntax

   The code uses '=' which is assignment, not comparison; it should be '=='.

2. Step 2: Validate other syntax parts

   Colon is present, continue is valid in loops, and range(4) is correct.

3. Final Answer:

   Using '=' instead of '==' in if condition -> Option B

4. Quick Check:

   Comparison needs '==' not '=' [OK]

Hint: Use '==' for comparison, '=' is assignment [OK]

Common Mistakes:

• Using '=' instead of '==' in conditions
• Thinking continue is invalid in loops
• Ignoring syntax errors

5. You want to print all numbers from 0 to 5 except 3 using a loop. Which code correctly uses loop control?

hard

A. for i in range(6):\n if i == 3:\n break\n print(i)

B. for i in range(6):\n if i == 3:\n pass\n print(i)

C. for i in range(6):\n if i != 3:\n break\n print(i)

D. for i in range(6):\n if i == 3:\n continue\n print(i)

Solution

1. Step 1: Understand the goal

   We want to skip printing 3 but continue printing other numbers from 0 to 5.

2. Step 2: Analyze each option

   for i in range(6):\n if i == 3:\n break\n print(i) stops loop at 3 (break), so numbers after 3 won't print. for i in range(6):\n if i == 3:\n continue\n print(i) skips 3 (continue) and prints others. for i in range(6):\n if i != 3:\n break\n print(i) breaks when number is not 3, stopping early. for i in range(6):\n if i == 3:\n pass\n print(i) uses pass which does nothing, so 3 is printed.

3. Final Answer:

   for i in range(6):\n if i == 3:\n continue\n print(i) -> Option D

4. Quick Check:

   Use continue to skip unwanted values [OK]

Hint: Use continue to skip, break to stop loop [OK]

Common Mistakes:

• Using break instead of continue to skip
• Using pass thinking it skips iteration
• Breaking loop too early