CODEWITHSUNDEEP
phparrayssplit
elfuego1
elfuego1

Reputation: 10348

Create rows of elements based on an array of length values

Is there a neat way to split an array into chunks based on an array of lengths?

Input:

$start = range(0, 30);
$length = [3, 7, 2, 12, 6];

Desired Output:

[
    [0, 1, 2],  // 3
    [4, 5, 6, 7, 8, 9, 10],  // 7
    [11, 12],  // 2
    [13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24],  // 12
    [25, 26, 27, 28, 29, 30],  // 6
];

Upvotes: 1

Views: 2318

Answers (2)

phant0m
phant0m

Reputation: 16905

Using array_splice:

$target = array(); // or use []  in PHP 5.4
foreach($length as $i) {
    $target[] = array_splice($start, 0, $i);
}

Try it.

Be advised, this changes $start!

Upvotes: 6

Joseph at SwiftOtter
Joseph at SwiftOtter

Reputation: 4321

This is very easily accomplished with the following:

Code:

$target = array();
$offset = 0;

foreach ($length as $lengthValue) {
    $target[] = array_slice($start, $offset, $lengthValue);
    $offset += $lengthValue;
}
var_dump($target);

Explanation:

What you are doing here is using the array_slice() method (very similar to the substr) to extract the portion of the array and then inserting it into the target array. Incrementing the offset each time allows the function to remember which one to use next time.

Upvotes: 2

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