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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;
}
}
?>
max
(PHP 4, PHP 5)
max — 최고값을 찾습니다
설명
하나의 인수만 배열로 주어지면, max()는 그 배열에서의 최고값을 반환합니다. 최소한 두 개의 인수가 주어지면, max()는 그 중에 최고값을 반환합니다.
Note:
PHP는 숫자가 아닌 string은 integer와 비교할 때 0으로 계산하지만, 그것이 가장 큰 값일 경우 그 문자열을 반환합니다. 0으로 계산된 여러 인수가 존재할 경우, max()는 존재할 경우 숫자 0을, 아니라면 알파벳 숫자 값이 가장 큰 문자열을 반환합니다.
인수
- values
-
값들을 가지는 배열.
반환값
max()는 수치적으로 가장 큰 인수 값을 반환합니다.
예제
Example #1 max()의 사용 예제
<?php
echo max(1, 3, 5, 6, 7); // 7
echo max(array(2, 4, 5)); // 5
echo max(0, 'hello'); // 0
echo max('hello', 0); // hello
echo max(-1, 'hello'); // hello
// 복수 배열일 경우, max는 왼쪽에서 오른쪽으로 비교합니다.
// 이 예제에서는: 2 == 2, 그 다음에 4 < 5
$val = max(array(2, 4, 8), array(2, 5, 7)); // array(2, 5, 7)
// 배열과 배열이 아닌것이 주어질 때는 배열 중에서
// 가장 큰 배열을 반환합니다.
$val = max('string', array(2, 5, 7), 42); // array(2, 5, 7)
?>
add a note
User Contributed Notes
max
toon dot baeyens at gmail dot com
07-May-2012 06:42
costinu
02-Feb-2012 06:21
max(null, 0) = null
max(0, null) = 0
sun at drupal dot org
03-Aug-2011 11:25
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.
php at rijkvanwel dot nl
12-Apr-2011 02:08
To get the largest key in an array:
<?php
$array = array( 0 => 'first', 1=> 'second', /* ... */ 99 => 'nth' );
$max_key = max( array_keys( $array ) ); // 99
?>
Alex Stanhope
28-Oct-2010 03:00
If you want to test whether x lies within two bounds:
<?php
static function isInRange($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);
}
?>
dan at coders dot co dot nz
22-May-2010 11:29
max() on undefined parameters does not assume the value is zero, it ignores it.
<?php
$dimensions = array('left' => -2);
// If $dimensions['right'] was never set,
// we may expect it to be treated as zero, but
print max($dimensions['left'], $dimensions['right']);
//
// Returns -2, not zero
print max(0+$dimensions['left'], 0+$dimensions['right']);
?>
would be a work-around, but it's probably tidier to ensure your values are set correctly first.
(on PHP 5.2.11 anyway)
Alex Rath
10-Apr-2010 11:27
Notice that whenever there is a Number in front of the String, it will be used for Comparison.
<?php
max('7iuwmssuxue', 1); //returns 7iuwmssuxu
max('-7suidha', -4); //returns -4
?>
But just if it is in front of the String
<?php
max('sdihatewin7wduiw', 3); //returns 3
?>
grillen at abendstille dot at
02-Apr-2010 03:55
max only accepts not empty arrays.
if you work a lot with numerical arrays and with max, this function may come in handy:
<?php
if (!function_exists('emax')) {
function emax($arr) {
if (!is_array($arr)) return call_user_func_array('max', func_get_args());
if (count($arr) == 0) return 0;
return max($arr);
}
}
?>
artem dot yagutyan at gmail dot com
27-Mar-2010 03:28
This Is Good Example: For max to min
<?php
function max_key($array) {
foreach ($array as $key => $val) {
if ($val == max($array)) return $key;
}
}
$array = array(10, 2, 5, 7, 4,15,32,8,41,25);
$array_count=count($array);
for($i=1;$i<=$array_count;$i++){
$max_val[$i]=max_key($array);
$view=$array[$max_val[$i]];
unset($array[$max_val[$i]]);
print $view."<br />"; //
}
/* OUTPUT
41 // Max
32
25
15
10
8
7
5
4
2 //Min
*/
?>
marcini
11-May-2009 07:34
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.
ries at vantwisk dot nl
09-Nov-2008 06:36
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
Marcus Zacco
29-Sep-2008 09:47
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 %
harmor
21-Feb-2008 09:56
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
michaelangel0 at mail.com
04-Jul-2007 03:00
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);
}
?>
jeremi23 at gmail dot com
14-Jun-2007 03:09
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.
johnmott59 at hotmail dot com
17-May-2007 12:35
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.
johnphayes at gmail dot com
02-May-2006 09:27
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