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max

(PHP 4, PHP 5)

maxMaximalwert bestimmen

Beschreibung

mixed max ( array $values )
mixed max ( mixed $value1 , mixed $value2 [, mixed $value3... ] )

Ist der erste und einzige Parameter ist ein Array, gibt max() den höchsten Wert dieses Arrays zurück. Sind mindestens zwei Parameter übergeben, gibt max() den größeren dieser Werte zurück.

Hinweis:

PHP evaluiert nicht-numerische string-Daten zu 0, wenn sie mit einem integer-Wert verglichen werden, gibt aber trotzdem die Zeichenkette zurück, wenn sie den numerisch höheren Wert hat. Werden mehrere Argumente zu 0 evaluiert, gibt max() den numerischen Wert 0, sofern er übergeben wurde, andernfalls den alphabetisch höchstwertigen String.

Parameter-Liste

values

Ein die Werte enthaltendes Array.

Rückgabewerte

max() liefert den numerisch größten Parameterwert zurück.

Beispiele

Beispiel #1 Verwendungsbeispiel von max()

<?php
echo max(13567);  // 7
echo max(array(245)); // 5

echo max(0'hello');     // 0
echo max('hello'0);     // hello
echo max(-1'hello');    // hello

// Bei multiplen Arrays vergleicht max von links nach rechts,
// daher ist in unserem Beispiel 2 == 2, aber 4 < 5
$val max(array(248), array(257)); // array(2, 5, 7)

// Sind ein Array und ein Nicht-Array-Parameter gegeben, wird immer
// das Array als größerer Wert angesehen
$val max('string', array(257), 42);   // array(2, 5, 7)
?>

Siehe auch

  • min() - Minimalwert bestimmen
  • count() - Zählt alle Elemente eines Arrays oder Attribute eines Objekts

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User Contributed Notes 18 notes

up
7
costinu
2 years ago
max(null, 0) = null
max(0, null) = 0
up
6
michaelangel0 at mail.com
7 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:

<?php
function doublemax($mylist){
 
$maxvalue=max($mylist);
  while(list(
$key,$value)=each($mylist)){
    if(
$value==$maxvalue)$maxindex=$key;
  }
  return array(
"m"=>$maxvalue,"i"=>$maxindex);
}
?>
up
5
php at rijkvanwel dot nl
3 years ago
To get the largest key in an array:

<?php
$array
= array( 0 => 'first', 1=> 'second', /* ... */ 99 => 'nth' );
$max_key = max( array_keys( $array ) ); // 99
?>
up
4
levim at php dot net
2 years ago
<?php
/**
* @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 {
       
$current = array_pop($stack );
        foreach (
$current as $value) {
            if (
is_array($value)) {
               
$stack[] = $value;
            } elseif (
filter_var($value, FILTER_VALIDATE_INT) !== FALSE) {
               
// max(NULL, 0) returns NULL, so cast it
               
$max = (int) max($max, $value);
            }
        }

    } while (!empty(
$stack));

    return
$max;
}
?>

- This function is not actually recursive, but fulfills the requirement that it works on sub-arrays.  I do this because PHP is not very good at recursion.  I also did it because I enjoy doing things this way. 
- It returns something of type int, never a string representation of an int. The exception is when you provide an array that does not contain any integers.  It will then return NULL.
- It ignores non-array, non-int values.
up
5
marcini
5 years ago
Note that max() can compare dates, so if you write something like this:

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

you will get: 2009-03-15.
up
4
Alex Rath
4 years ago
Notice that whenever there is a Number in front of the String, it will be used for Comparison.

<?php

  max
('7iuwmssuxue', 1); //returns 7iuwmssuxu
 
max('-7suidha', -4); //returns -4

?>

But just if it is in front of the String

<?php

  max
('sdihatewin7wduiw', 3); //returns 3

?>
up
3
johnphayes at gmail dot com
8 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
up
2
harmor
6 years ago
A way to bound a integer between two values is:

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

which is the same as:

<?php
$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:
<?php
$x
= 0;
echo
bound(0, 1, 12).'<br />';
$x = 1;
echo
bound($x, 1, 12).'<br />';
$x = 6;
echo
bound($x, 1, 12).'<br />';
$x = 12;
echo
bound($x, 1, 12).'<br />';
$x = 13;
echo
bound($x, 1, 12).'<br />';
?>

Output:
1
1
6
12
12
up
1
Alex Stanhope
3 years ago
If you want to test whether x lies within two bounds:

<?php
   
static function isInRange($x, $y1, $y2) {
        return( (
$x >= min($y1, $y2)) && ($x <= max($y1, $y2)) );
    }

//called by:

  
class::isInRange(10,12,2);
//or
  
$this->isInRange(10,12,2);
//or (drop static)
  
isInRange(10,12,2);

//simple test function:

   
static function unit_isInRange() {
       
$output = array();
       
$inputlist[] = array(10, 12, 2, true);
       
$inputlist[] = array(13, 12, 2, false);
       
$inputlist[] = array(2, -2, 2, true);
       
$inputlist[] = array(2, -8, -2, false);
        foreach(
$inputlist as $input) {
           
$output[] = array(
               
'input' => array($input[0], $input[1], $input[2]),
               
'output' => self::isInRange($input[0],$input[1],$input[2]),
               
'expected' => $input[3],
            );
        }
        return(
$output);
    }
?>
up
1
jeremi23 at gmail dot com
7 years ago
max on a an array with key/values

<?php
$tmp
= array(1 => 5, 2=> 3);
echo
max($tmp);
?>

this return 5, so the max is done on the values.
up
1
johnmott59 at hotmail dot com
7 years ago
To find the maximum value from a set of 1-dimensional arrays, do this:

<?php
$d1
= array(450,420,440,430,421);
$d2 = array(460,410,410,430,413,375,256,411,656);
$d3 = array(430,440,470,435,434,255,198);

$t = max(max($d1),max($d2),max($d3));
// $t is 656
?>

The inner max() functions operate on the arrays, the outer max compares the numeric results of the inner ones.
up
2
volch5 at gmail dot com
4 months ago
max() (and min()) on DateTime objects compares them like dates (with timezone info) and returns DateTime object.
<?php
$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
up
1
toon dot baeyens at gmail dot com
2 years ago
A little function for multi-dimensional arrays:
<?php
function amax($array){
    if(
is_array($array)){
        foreach(
$array as $key => $value){
           
$array[$key] = amax($value);
        }
        return
max($array);
    }else{
        return
$array;
    }
}
?>
up
0
ReVo_
3 months ago
Sometimes you could need to get the max from an array which looks like this:

<?php
$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"

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

    return
$currentMax;
}

//                                            array       key
$value = maxValueInArray($arrTest, "b");

?>

output: 43
up
0
sun at drupal dot org
3 years ago
Note that max() throws a warning if the array is empty:

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

So make sure your data isn't empty.
up
0
grillen at abendstille dot at
4 years ago
max only accepts not empty arrays.

if you work a lot with numerical arrays and with max, this function may come in handy:

<?php
if (!function_exists('emax')) {
    function
emax($arr) {
        if (!
is_array($arr)) return call_user_func_array('max', func_get_args());
        if (
count($arr) == 0) return 0;
        return
max($arr);
    }
}
?>
up
0
ries at vantwisk dot nl
5 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
up
0
Marcus Zacco
5 years ago
This code loops through seven arrays and finds the highest average value within those arrays - and changes the font color for it. Great for highlighting.

The biggest take-away is this the row
if($average[$i] == max($average))

The number_format just rounds the numbers to 0 decimal points.

<?php
for ( $i = 0; $i <= 6; $i++) {
 
$num = $i+1;
  if(
$average[$i] == max($average)) {
    echo
"Value ".$num.": <font color='red'>".number_format($average[$i], 0, '.', '')." % </font<br>";
  } else {
    echo
"Value ".$num.": ".number_format($average[$i],0,'.','')." %<br>";
  }
}
?>

### OUTPUT

Value 1: 52 %
Value 2: 58 %
Value 3: 56 %
Value 4: 73 %
Value 5: 77 % <- this 77 is highlighted in red
Value 6: 71 %
Value 7: 75 %
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