Search for highest key/index in an array
PhpArraysKeyHighestPhp Problem Overview
How can I get the highest key/index in an array with [tag:PHP]? I know how to do it for the values.
E.g.: from this array I would like to get 10 as an integer value:
$arr = array(1 => "A", 10 => "B", 5 => "C");
I know how I could code it but I was asking myself if there is a function for this as well.
Php Solutions
Solution 1 - Php
This should work fine
$arr = array( 1 => "A", 10 => "B", 5 => "C" );
max(array_keys($arr));
Solution 2 - Php
You can get the maximum key this way:
<?php
$arr = array("a"=>"test", "b"=>"ztest");
$max = max(array_keys($arr));
?>
Solution 3 - Php
I had a situation where I needed to obtain the next available key in an array, which is the highest + 1.
For example, if the array is $data = ['1' => 'something, '34' => 'something else'], then I needed to calculate 35 to add a new element to the array that had a key higher than any of the others. In the case of an empty array I needed 1 as next available key.
This is the solution that worked:
$highest = 0;
foreach ($data as $idx => $dummy) {
if ($idx > $highest) $highest = $idx;
}
$highest++;
It will work in all cases, empty array or not. If you only need to find the highest key rather than highest key + 1, delete the last line.
You will then get a value of 0 if the array is empty.
Solution 4 - Php
$keys = array_keys($arr);
$keys = rsort($keys);
print $keys[0];
should print "10"
Solution 5 - Php
function getMaxKey(array $array): ?int
{
if ($array === []) {
return null;
}
return max(0, ...array_keys($array));
}
assuming you don't have negative keys like int -1
Solution 6 - Php
Try max() function, see the first comment on that page.
Solution 7 - Php
$higestKey = 0;
foreach ($data as $key => $value) {
if (strlen($key) > $higestKey) $higestKey = strlen($key);
}