[Solved] What will be the output of the following PHP code?$numbers = [1, 2, 3]; array_walk($numbers, function(&$value) { $value *= 2; }); print_r($numbers); | PHP

PHP - Array Functions

What will be the output of the following PHP code?

$numbers = [1, 2, 3];
array_walk($numbers, function(&$value) {
    $value *= 2;
});
print_r($numbers);

AArray ( [0] => 2 [1] => 4 [2] => 6 )

BArray ( [0] => 1 [1] => 2 [2] => 3 )

CArray ( [0] => 0 [1] => 0 [2] => 0 )

DError: Cannot modify array elements

Step-by-Step Solution

Solution:

Step 1: Understand the callback function
The callback multiplies each value by 2, and the value is passed by reference (&$value), so changes affect the original array.
Step 2: Apply changes to each element
1*2=2, 2*2=4, 3*2=6, so the array becomes [2, 4, 6].
Final Answer:
Array ( [0] => 2 [1] => 4 [2] => 6 ) -> Option A
Quick Check:
Reference callback doubles values [OK]

Quick Trick: Pass value by reference to modify array items [OK]

Common Mistakes:

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