php – How can i take an array, divide it by two and create two lists?

To get a part of an array, you can use array_slice:

$input = array("a", "b", "c", "d", "e");

$len = count($input);

$firsthalf = array_slice($input, 0, $len / 2);
$secondhalf = array_slice($input, $len / 2);

Use array_chunk to split the array up into multiple sub-arrays, and then loop over each.

To find out how large the chunks should be to divide the array in half, use ceil(count($array) / 2).

<?php
$input_array = array('a', 'b', 'c', 'd', 'e', 'f');
$arrays = array_chunk($input_array, 3);

foreach ($arrays as $array_num => $array) {
  echo "Array $array_num:\n";
  foreach ($array as $item_num => $item) {
    echo "  Item $item_num: $item\n";
  }
}

Output

Array 0:
  Item 0: a
  Item 1: b
  Item 2: c
Array 1:
  Item 0: d
  Item 1: e
  Item 2: f

http://php.net/manual/en/function.array-slice.php

To slice the array into half, use floor(count($array)/2) to know your offset.

$limit=count($array);

$first_limit=$limit/2;
for($i=0;$i<$first; $i++)
{
  echo $array[$i];
}
foreach ($i=$first; $i< $limit; $i++)
{
  echo $array[$i];
}

Here’s a one-liner which uses array_chunk:

list($part1, $part2) = array_chunk($array, ceil(count($array) / 2));

If you need to preserve keys, add true as the third argument:

list($part1, $part2) = array_chunk($array, ceil(count($array) / 2), true);

Using a foreach loop you could do this:

$myarray = array("a", "b", "c", "d", "e", "f", "g");
$array1 = array();
$array2 = array();
$i = 1;

foreach ($myarray as $value) {
    if ($i <= count($myarray) / 2) {
        $array1[] = $value;
    } else {
        $array2[] = $value;
    }
    $i++;
}

But it’s even easier to use array_splice

$myarray = array("a", "b", "c", "d", "e", "f", "g");
$array1 = array_splice($myarray, 0, floor(count($myarray)/2));
$array2 = $myarray;

This Worked for me made the first array always a little longer. Thought this might help people too.

$firsthalf = array_slice($input, 0, $len / 2 +1);
$secondhalf = array_slice($input, $len / 2 +1);