How to convert flat array to a multidimensional array?

Question

What is the best way to convert array like:

array(1,2,3,4,5,6,7,8,9,10)

to:

  array(
    array(1,2,3),
    array(4,5,6),
    array(7,8,9),
    array(10),
  );

I came up with something like:

$flat = array(1,2,3,4,5,6,7,8,9,10);
$colsLimit = 3;
$offset = 0;
$multi = array();

while($sliced = array_slice($flat, $offset, $colsLimit)) {
  $multi[] = $sliced;
  $offset += 3;
}

A better solutions are welcome.

Check the "See also" section of array_slice documentation page — zerkms
– zerkms, Commented Dec 16, 2013 at 21:16

Amal · Accepted Answer · 2013-12-16 21:20:22Z

1

PHP has a built-in function that does exactly this: array_chunk():

Chunks an array into arrays with size elements. The last chunk may contain less than size elements.

Usage:

$arr = array(1,2,3,4,5,6,7,8,9,10);
$result = array_chunk($arr, 3);

Demo.

answered Dec 16, 2013 at 21:20

Amal

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Uours · Accepted Answer · 2013-12-16 23:30:28Z

1

A different approach using neither array_slice nor array_chunk

$flat = array( 1 ,2 ,3 ,4 ,5 ,6 ,7 ,8 ,9 ,10 );

$multi = array( ( $multiIndex = 0 ) => array( ) );

foreach( $flat as $value )
      count( $multi[ $multiIndex ] ) == 3
    ? $multi[ ++$multiIndex ] = array( $value )
    : $multi[ $multiIndex ][ ] = $value
    ;

var_dump( $multi );

answered Dec 16, 2013 at 23:30

Uours

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