How to get array max value in php?

(PHP 4, PHP 5, PHP 7, PHP 8)

max — Find highest value

Description

Alternative signature (not supported with named arguments):

max(array $value_array): mixed

Note:

Values of different types will be compared using the standard comparison rules. For instance, a non-numeric string will be compared to an int as though it were 0, but multiple non-numeric string values will be compared alphanumerically. The actual value returned will be of the original type with no conversion applied.

Caution

Be careful when passing arguments of different types because max() can produce unpredictable results.

Parameters

Any comparable value.

Any comparable values.

An array containing the values.

Return Values

max() returns the parameter value considered "highest" according to standard comparisons. If multiple values of different types evaluate as equal (e.g. 0 and 'abc') the first provided to the function will be returned.

If an empty array is passed, then false will be returned and an E_WARNING error will be emitted.

Examples

Example #1 Example uses of max()

echo max(2, 3, 1, 6, 7);  // 7
echo max(array(2, 4, 5)); // 5

// The string 'hello' when compared to an int is treated as 0
// Since the two values are equal, the order they are provided determines the result

See Also

• min() - Find lowest value
• count() - Counts all elements in an array or in a Countable object

keith at bifugi dot com ¶

6 years ago

The simplest way to get around the fact that max() won't give the key is array_search:

$student_grades = array ("john" => 100, "sarah" => 90, "anne" => 100);
$top_student = array_search(max($student_grades),$student_grades); // john
?>

This could also be done with array_flip, though overwriting will mean that it gets the last max value rather than the first:

$grades_index = array_flip($student_grades);
$top_student = $grades_index[max($student_grades)]; // anne
?>

To get all the max value keys:

$top_students = array_keys($student_grades,max($student_grades)); // john, anne
?>

deoomen ¶

3 months ago

Watch out after PHP 8.0!

Sample code:

echo max(0,'hello');
?>

Before PHP 8.0 will return int(0) but since PHP 8.0 above code returns string("hello")!!

volch5 at gmail dot com ¶

8 years ago

max() (and min()) on DateTime objects compares them like dates (with timezone info) and returns DateTime object.
$dt1 = new DateTime('2014-05-07 18:53', new DateTimeZone('Europe/Kiev'));
$dt2 = new DateTime('2014-05-07 16:53', new DateTimeZone('UTC'));
echo max($dt1,$dt2)->format(DateTime::RFC3339) . PHP_EOL; // 2014-05-07T16:53:00+00:00
echo min($dt1,$dt2)->format(DateTime::RFC3339) . PHP_EOL; // 2014-05-07T18:53:00+03:00
?>

It works at least 5.3.3-7+squeeze17

marcini ¶

13 years ago

Note that max() can compare dates, so if you write something like this:

$dates = array('2009-02-15', '2009-03-15');
echo max($dates);
?>

you will get: 2009-03-15.

costinu ¶

10 years ago

max(null, 0) = null
max(0, null) = 0

Alex Rath ¶

12 years ago

Notice that whenever there is a Number in front of the String, it will be used for Comparison.

  max

ries at vantwisk dot nl ¶

13 years ago

I had several occasions that using max is a lot slower then using a if/then/else construct. Be sure to check this in your routines!

Ries

ReVo_ ¶

8 years ago

Sometimes you could need to get the max from an array which looks like this:

$arrTest = array(
    array( "day" => 1, "b" => 10 ),
    array( "day" => 2, "b" => 43 ),
    array( "day" => 3, "b" => 2 ),
    array( "day" => 4, "b" => -3 ),
    array( "day" => 5, "b" => 4 ),
    array( "day" => 6, "b" => -5 )
);
?>
all max functions i see around don't provide a way to get the max value of the values in (example) key "b"

function maxValueInArray($array, $keyToSearch)
{
    $currentMax = NULL;
    foreach($array as $arr)
    {
        foreach($arr as $key => $value)
        {
            if ($key == $keyToSearch && ($value >= $currentMax))
            {
                $currentMax = $value;
            }
        }
    }

    return

michaelangel0 at mail.com ¶

15 years ago

Matlab users and others may feel lonely without the double argument output from min and max functions.

To have the INDEX of the highest value in an array, as well as the value itself, use the following, or a derivative:

function doublemax($mylist){
  $maxvalue=max($mylist);
  while(list($key,$value)=each($mylist)){
    if($value==$maxvalue)$maxindex=$key;
  }
  return array("m"=>$maxvalue,"i"=>$maxindex);
}
?>

johnphayes at gmail dot com ¶

16 years ago

Regarding boolean parameters in min() and max():

(a) If any of your parameters is boolean, max and min will cast the rest of them to boolean to do the comparison.
(b) true > false
(c) However, max and min will return the actual parameter value that wins the comparison (not the cast).

Here's some test cases to illustrate:

1.  max(true,100)=true
2.  max(true,0)=true
3.  max(100,true)=100
4.  max(false,100)=100
5.  max(100,false)=100
6.  min(true,100)=true
7.  min(true,0)=0
8.  min(100,true)=100
9.  min(false,100)=false
10. min(100,false)=false
11. min(true,false)=false
12. max(true,false)=true

php at rijkvanwel dot nl ¶

11 years ago

To get the largest key in an array:

$array = array( 0 => 'first', 1=> 'second', /* ... */ 99 => 'nth' );
$max_key = max( array_keys( $array ) ); // 99
?>

sun at drupal dot org ¶

11 years ago

Note that max() throws a warning if the array is empty:

$a = array();
max($a);
// Warning: max(): Array must contain at least one element
?>

So make sure your data isn't empty.

info at osworx dot net ¶

3 years ago

Be aware if a array like this is used (e.g. values from a shopping cart):
Array
(
    [0] => 142,80
    [1] => 39,27
    [2] => 22,80
    [3] => 175,80
)?>
The result will be: 39,27 and not - as expected - 175,80

So, to find the max value, use integer only like:
Array
(
    [0] => 14280
    [1] => 3927
    [2] => 2280
    [3] => 17580
)?>
and you will get the correct result: 17580

harmor ¶

14 years ago

A way to bound a integer between two values is:

function bound($x, $min, $max)
{
     return min(max($x, $min), $max);
}
?>

which is the same as:

$tmp = $x;
if($tmp < $min)
{
    $tmp = $min;
}
if($tmp > $max)
{
     $tmp = $max;
}
$y = $tmp;
?>

So if you wanted to bound an integer between 1 and 12 for example:

Input:
$x = 0;
echo bound(0, 1, 12).'
';
$x = 1;
echo bound($x, 1, 12).'
';
$x = 6;
echo bound($x, 1, 12).'
';
$x = 12;
echo bound($x, 1, 12).'
';
$x = 13;
echo bound($x, 1, 12).'
';
?>

Output:
1
1
6
12
12

blackmac01 at gmail dot com ¶

2 years ago

In response to: keith at bifugi dot com

If you want to find the specific key(s) that match the maximum value in an array where the values may be duplicated, you can loop through and perform a simple check:
# Example Array
$a = array(
     'key1' => 100,
     'key2' => 90,
     'key3' => 100,
     'key4' => 90,
);# First get the maximum value
$max = max($a);# Create a new array containing all keys which have the max value
foreach($a as $key => $val) {    
     if($val === $max) $b[] = $key;
}# If you want a string list, just do this
$b = implode(' ', $b);
?>

This produces consistent results and will scale well in terms of performance, whereas functions like array_search and array_flip can lead to degraded performance when dealing with large amounts of data.

levim at php dot net ¶

10 years ago

/**
* @param array $array
*
* @return int|null Returns the largest value of the array. Returns NULL if no
*     integers are found.
*/
function array_max_recursive(array $array) {
    $max = NULL;
    $stack = array($array);

    do {

toon dot baeyens at gmail dot com ¶

10 years ago

A little function for multi-dimensional arrays:
function amax($array){
    if(is_array($array)){
        foreach($array as $key => $value){
            $array[$key] = amax($value);
        }
        return max($array);
    }else{
        return $array;
    }
}
?>

Michael Blinn ¶

3 years ago

Be careful using max() with objects, as it returns a reference not a new object.

$min_date

chris at candm dt org dt uk ¶

1 year ago

A function to return the key of the max value of an array. For multiple max values, it will return the key of first. Change > to >= to get the last.

function array_max_key($arr) {
    $maxkey='';
    $maxval=false;
    array_walk($arr,
        function (&$cval,&$ckey) use(&$maxkey,&$maxval) {
            if ($maxval === false || $cval > $maxval) {
                $maxval = $cval;
                $maxkey = $ckey;
            }
        }
    );
    return $maxkey;
}