Which of the following callback functions can be used with array_filter to keep only even numbers?

easy📝 Conceptual Q2 of 15

PHP - Array Functions

Which of the following callback functions can be used with array_filter to keep only even numbers?

Afunction($n) { return $n > 0; }

Bfunction($n) { return $n % 2 === 0; }

Cfunction($n) { return $n < 0; }

Dfunction($n) { return $n === 1; }

Step-by-Step Solution

Solution:

Step 1: Identify the condition for even numbers
Even numbers are divisible by 2 with no remainder, so $n % 2 === 0 checks this.
Step 2: Check other options
Other options check positivity, negativity, or equality to 1, which do not filter even numbers.
Final Answer:
function($n) { return $n % 2 === 0; } -> Option B
Quick Check:
Callback for even numbers = $n % 2 === 0 [OK]

Quick Trick: Use modulo operator % to test even numbers [OK]

Common Mistakes:

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