Array chunk and pad in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the PHP function array_chunk() do?

It splits an array into smaller arrays (chunks) of a specified size. Each chunk is a new array containing elements from the original array.

beginner

How does array_pad() work in PHP?

It adds elements to an array until it reaches a specified size. You can add elements at the end (positive size) or at the beginning (negative size).

intermediate

What happens if the size parameter in array_chunk() is larger than the array length?

The function returns one chunk containing the entire original array because it cannot split into smaller chunks.

intermediate

Can array_pad() shrink an array if the size is smaller than the current array length?

No, array_pad() only adds elements if the array is smaller than the specified size. It does not remove elements.

beginner

Show a simple example of using array_chunk() and array_pad() together.

Example:<br>

$arr = [1, 2, 3, 4];
$chunks = array_chunk($arr, 2); // [[1, 2], [3, 4]]
$padded = array_pad($chunks[0], 4, 0); // [1, 2, 0, 0]

What does array_chunk([1,2,3,4,5], 2) return?

A [[1,2], [3,4], [5]]

B [[1,2,3], [4,5]]

C [[1,2], [3,4,5]]

D [[1], [2], [3], [4], [5]]

The array is split into chunks of size 2. The last chunk contains the remaining element.

What will array_pad([1,2], 5, 0) return?

A [1, 2, 5]

B [1, 2]

C [0, 0, 1, 2]

D [1, 2, 0, 0, 0]

The array is padded at the end with zeros until it reaches size 5.

If you use array_pad([1,2,3], -5, 'x'), where are the elements added?

A At the end

B At the beginning

C No elements are added

D Elements replace existing ones

A negative size pads the array at the beginning.

What happens if you call array_chunk([1,2,3], 10)?

A [[1,2,3]]

B []

C [[1,2], [3]]

D Error

Since chunk size is larger than array length, the whole array is one chunk.

Does array_pad() remove elements if the array is bigger than the size?

A Yes, it removes extra elements

B It throws an error

C No, it only adds elements

D It duplicates elements

array_pad only adds elements; it never removes them.

Explain how you can split an array into smaller parts and then make sure each part has the same length by adding extra elements.

Think about splitting first, then adding elements to chunks.

Describe the difference between positive and negative size values in array_pad.

Where do new elements go depending on sign of size?