63

I'm trying to get hold of the largest value in an array, while still preserving the item labels. I know I can do this by running sort(), but if I do so I simply lose the labels - which makes it pointless for what I need. Here's the array:

array("a"=>1,"b"=>2,"c"=>4,"d"=>5);

Any ideas?

17 Answers 17

173

Don't sort the array to get the largest value.

Get the max value:

$value = max($array);

Get the corresponding key:

$key = array_search($value, $array);
3
  • Why not array_max() dear php. 🤔 Note that this function will not return an int if your values are of the string type. (even if they contain integers). So best to do $value = (int) max($array);
    – COil
    Commented Nov 13, 2018 at 17:00
  • 5
    max($array) is not going to work if two keys have the same max value. Commented Apr 25, 2019 at 17:03
  • you know the max value, so loop through array to get matching IDs Commented Oct 22, 2019 at 13:54
25

If you just want the largest value in the array use the max function. This will return the largest value, although not the corresponding key. It does not change the original array.

If you care about the the key you could then do

$key = array_search(max($array), $array)

(Edited to include @binaryLV's suggestion)

1
6
$a = array(10, 20, 52, 105, 56, 89, 96);
$b = 0;
foreach ($a as $key=>$val) {
    if ($val > $b) {
        $b = $val;
    }
}
echo $b;
5

You are looking for asort()

6
  • 1
    If you don't need the whole array sorted, use one of the gazillion other answers obviously ;) But mentioning sort() made me think you phrased your question wrong.
    – Jacob
    Commented Jul 13, 2011 at 9:43
  • Jacob is right - doing an asort will reorder the array lowest to highest maintaining keys...then do a foreach and the $key=>$value from that will be set to the highest pair after the foreach completes..so you have the highest one right there - the key and the value... Commented Aug 23, 2019 at 0:06
  • If we use sort() or asort() it may lead to time complexity with n nodes
    – chandru
    Commented Nov 15, 2021 at 16:35
  • @chandru Which is good or bad? Commented Aug 5, 2022 at 11:31
  • 1
    @Stranger ...which is not necessary for this question/page. A loop (instead of sorting) will be "linear" and therefore will boast better performance. Commented Jan 10, 2023 at 0:50
5

You could use max() for getting the largest value, but it will return just a value without an according index of array. Then, you could use array_search() to find the according key.

$array = array("a"=>1,"b"=>2,"c"=>4,"d"=>5);
$maxValue = max($array);
$maxIndex = array_search(max($array), $array);
var_dump($maxValue, $maxIndex);

Output:

int 5
string 'd' (length=1)

If there are multiple elements with the same value, you'll have to loop through array to get all the keys.

It's difficult to suggest something good without knowing the problem. Why do you need it? What is the input, what is the desired output?

1

greatestValue=> try this its very easy

$a=array(10,20,52,105,56,89,96);
$c=0;
foreach($a as $b)
{
if($b>$c)
$c=$b;

}
echo $c;
1
$ee = array('a' => 50, 'b' => 25, 'c' => 5, 'd' => 80, 'e' => 40, 'f' => 152, 'g' => 45, 'h' => 28);
$Acurr = '';
$Amax = 0;

foreach($ee as $key => $value) {
    $Acurr = $value;    

    if($Acurr >= $Amax) {
        $Amax = $Acurr; 
    }
}

echo "greatest number is $Amax";
1

Try it.

$data = array("a"=>1,"b"=>2,"c"=>4,"d"=>5); $maxKey = current(array_keys($data, max($data))); var_dump($maxKey);

1
  • 3
    Welcome to Stack Overflow. Eight year old questions with fifteen existing answers require more than a code only answer. It is very important to point out what new aspect of the question your answer addresses. All answers can generally benefit from explaining how and why they work as well. Commented Jun 6, 2020 at 18:39
0
// assuming positive numbers

$highest_key;
$highest_value = 0;
foreach ($array as $key => $value) {
    if ($value > $highest_value) {
        $highest_key = $key;
    }
}

// $highest_key holds the highest value
0
$abc=array("a"=>1,"b"=>2,"c"=>4,"e"=>7,"d"=>5);
/*program to find max value*/
$lagest = array();
$i=0;
foreach($abc as $key=>$a) {
    if($i==0) $b=$a;
    if($b<$a) {
        $b=$a;
        $k=$key;
    }
    $i++;
 }
 $lagest[$k]=$b;
 print_r($lagest);
0
<?php 
$array = array("a"=>1,"b"=>2,"c"=>4,"d"=>5); 

foreach ($array as $key => $value) {
   if ($value >= $max) 
    $max = $key;     
}
echo " The array in largest number :".$max."<br/>";
?> 
0

Find highest number, including negative:

return max([abs(max($array)),abs(min($array))]);
-1

asort() is the way to go:

$array = array("a"=>1,"b"=>2,"c"=>4,"d"=>5);
asort($array);
$highestValue       = end($array);
$keyForHighestValue = key($array);
-1

You need to use by ksort(array("a"=>1,"b"=>2,"c"=>4,"d"=>5)); for more info: http://www.w3schools.com/php/php_arrays_sort.asp

0
-1

Here a solution inside an exercise:

function high($sentence)
{
    $alphabet = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'ñ', 'o', 'p', 'q', 'r', 't', 'u', 'v', 'w', 'x', 'y', 'z'];
    $alphabet = array_flip($alphabet);

    $words = explode(" ", $sentence);

    foreach ($words as $word) {
        $letters = str_split($word);
        $points = 0;
        foreach ($letters as $letter)
            $points += $alphabet[$letter];
        $score[$word] = $points;
    }

    $value = max($score);
    $key = array_search($value, $score);

    return $key;
}

echo high("what time are we climbing up the volcano");
1
  • This unexplained answer is too convoluted and too far from the asked question. Commented Jan 10, 2023 at 2:25
-1

Find largest number without using built-in functions in PHP

<?php
    $array = array(1,2,3);
    $flag = 0;
    foreach($array as $key=>$val){
        if($val > $flag){
           $flag = $val;
        }
        echo "Max value with each iteration: ".$flag."<br/>";
    }
    echo "Final max value: ".$flag;
    ?>
1
  • This technique was posted by a user in 2013 and multiple users on this page back in 2015. Commented Jan 10, 2023 at 2:24
-3

Try using asort().

From documentation:

asort - Sort an array and maintain index association

Description:

bool asort ( array &$array [, int $sort_flags = SORT_REGULAR ] )

This function sorts an array such that array indices maintain their correlation with the array elements they are associated with. This is used mainly when sorting associative arrays where the actual element order is significant.

1
  • What is it you are proposing different?
    – lomse
    Commented May 21, 2013 at 11:40

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