Python Coding Challange - Question With Answer(01281224)

 

What will the following code output?

print([x**2 for x in range(10) if x % 2 == 0])

• [0, 1, 4, 9, 16]

• [0, 4, 16, 36, 64]

• [4, 16, 36, 64]

• [1, 4, 9, 16, 25]

1. List Comprehension Syntax

This code uses list comprehension, a concise way to create lists in Python. The general structure is:

[expression for item in iterable if condition]

• expression: What you want to compute for each item.
• item: The current element from the iterable.
• iterable: A sequence, such as a list or range.
• if condition: A filter to include only items that satisfy the condition.

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2. Components of the Code

a. range(10)

• range(10) generates numbers from 0 to 9.

b. if x % 2 == 0

• This is the filter condition.
• x % 2 calculates the remainder when x is divided by 2.
  • If the remainder is 0, the number is even.
• This condition selects only the even numbers from 0 to 9.

c. x**2

• For each even number, x**2 computes the square of x.

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3. Step-by-Step Execution

Step 1: Generate Numbers from range(10)

The numbers are:

0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Step 2: Apply the Condition if x % 2 == 0

Keep only even numbers:

0, 2, 4, 6, 8

Step 3: Compute the Expression x**2

Calculate the square of each even number:

• $0^2 = 0$
• $2^2 = 4$
• $4^2 = 16$
• $6^2 = 36$
• $8^2 = 64$

Step 4: Create the Final List

The resulting list is:

[0, 4, 16, 36, 64]

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4. Output

The code prints:

[0, 4, 16, 36, 64]