log
A quick addendum to the comment left by "sumeruter": the recursive property will only work if all the sub-arrays are exactly the same length. Otherwise it will just return the longest array every time.
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 Notesmax
soapergem at gmail dot com
08-Jul-2009 04:58
08-Jul-2009 04:58
marcini
11-May-2009 11:34
11-May-2009 11:34
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.
sumeruter+php add an at gmail dot com
10-Dec-2008 08:54
10-Dec-2008 08:54
An interesting feature not mentioned is that if a recursive array is passed to max, max will return the sub-array containing the highest value.
Example:
<?php
$depth3=array(
array(array(1,6,3),array(7,2,5),array(9,3,0)),
array(array(2,1,8),array(4,4,5),array( 99 ,6,7)),
array(array(0,3,2),array(5,91,11),array(42,25,12)));
$depth2=max($depth3);
// = array(array(2,1,8),array(4,4,5),array( 99 ,6,7))
$depth1=max($depth2);
// = array( 99 ,6,7)
$depth0=max($depth1);
// = 99
echo max(max(max($depth3)));
// echo 99;
?>
ries at vantwisk dot nl
09-Nov-2008 11:36
09-Nov-2008 11:36
I had several occasions that using max is a lot slower then using a if/then/else construct. Be sure to check this in your routines!
Ries
Marcus Zacco
30-Sep-2008 01:47
30-Sep-2008 01:47
This code loops through seven arrays and finds the highest average value within those arrays - and changes the font color for it. Great for highlighting.
The biggest take-away is this the row
if($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 %
henk at tobbe dot net dot au
16-Apr-2008 04:05
16-Apr-2008 04:05
In a publication by WROX I noted a variant of the earlier "bound" function:
A parameter had to be between 1 and 3...
$par=round((min(max($x,1),3));
stuff at necr0manzer dot de
03-Mar-2008 04:11
03-Mar-2008 04:11
mick at wireframe dot com's solution to finding the key for the highest value didn't work for me, so I wrote one myself:
<?php
function max_key($array) {
foreach ($array as $key => $val) {
if ($val == max($array)) return $key;
}
}
$array = array(1, 2, 5, 7, 4);
echo max($array); // 7
echo max_key($array); // 3
?>
of course this also works with associative arrays, but it will only return a single result!
harmor
22-Feb-2008 02:56
22-Feb-2008 02:56
A way to bound a integer between two values is:
function bound($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).'<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
mick at wireframe dot com
31-Oct-2007 08:51
31-Oct-2007 08:51
There are a couple of things you can do for cleaner code if you want the keys returned from the array. I am not sure how they each impact performance, but the visual readability is more beneficial for me -- your mileage may vary.
In the first example keys and max value is returned:
<?php
// First, let's pretend we have an array like this:
$Some_Array = array(
'john' => 40,
'susan' => 40,
'jane' => 24,
'michael' => 19,
'jimmy' => 38
);
function max_extract($My_Array) {
$Max_Value = max($My_Array);
return array_fill_keys(array_keys($My_Array, $Max_Value), $Max_Value);
} // ! max_extract()
?>
Or, if you are only interested in the keys and don't care what the max is:
<?php
function max_extract($My_Array) {
return array_keys($My_Array, max($My_Array));
// You can also array_flip() this is you want them as keys
// or if some other reason makes this relevant/needed.
} // ! max_extract()
?>
There are many possible variations when using the search parameter of array_keys() along with other array functions.
sta
08-Sep-2007 01:05
08-Sep-2007 01:05
Or to take multiple maximum values into consideration:
function doublemax($mylist){
$maxvalue=max($mylist);
$max_keys = array();
while(list($key,$value)=each($mylist)){
if($value==$maxvalue)
array_push($max_keys,$key);
}
return $max_keys;
}
joan dot codina at upf dot edu
15-Jul-2007 02:11
15-Jul-2007 02:11
This is highly ineficient, but can be a bit better
<?
function doublemax($mylist){
$maxvalue=max($mylist);
while(list($key,$value)=each($mylist)){
if($value==$maxvalue)
return array("key"=>$key,"value"=>$value);
}
}
?>
michaelangel0 at mail.com
05-Jul-2007 07:00
05-Jul-2007 07:00
Matlab users and others may feel lonely without the double argument output from min and max functions.
To have the INDEX of the highest value in an array, as well as the value itself, use the following, or a derivative:
<?
function doublemax($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 07:09
14-Jun-2007 07:09
max on a an array with key/values
<?
$tmp = array(1 => 5, 2=> 3);
echo max($tmp);
?>
this return 5, so the max is done on the values.
johnmott59 at hotmail dot com
18-May-2007 04:35
18-May-2007 04:35
To find the maximum value from a set of 1-dimensional arrays, do this:
$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
03-May-2006 01:27
03-May-2006 01:27
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
tim at (NOSPAM) dot crazynot2 dot com
08-Nov-2005 06:56
08-Nov-2005 06:56
In response to the previous two posters (zher0 at netcarrier dot com & walkingmantis):
I was trying to do exactly what zher0 suggested; calculate the max value of a multi-dimensional array with variably sized 'sub-arrays'. Here is a simple little function I came up with to do just that:
<?php
function multimax( $array ) {
// use foreach to iterate over our input array.
foreach( $array as $value ) {
// check if $value is an array...
if( is_array($value) ) {
// ... $value is an array so recursively pass it into multimax() to
// determine it's highest value.
$subvalue = multimax($value);
// if the returned $subvalue is greater than our current highest value,
// set it as our $return value.
if( $subvalue > $return ) {
$return = $subvalue;
}
} elseif($value > $return) {
// ... $value is not an array so set the return variable if it's greater
// than our highest value so far.
$return = $value;
}
}
// return (what should be) the highest value from any dimension.
return $return;
}
?>
Please note that I have only performed very limited testing on this code -- be sure to check it thoroughly if you implement it somewhere!
nonick AT 8027 DOT org
18-Dec-2003 12:50
18-Dec-2003 12:50
If you are working with numbers, then you can use:
$a = ($b > $c) ? $b : $c;
which is somewhat faster (roughly 16%) than
$a = max($b, $c);
I tested this on several loops using integers and floats, over 1 million iterations.
I'm running PHP 4.3.1 as a module for Apache 1.3.27.
mikhail_kovalev at mail dot ru
14-May-2003 08:32
14-May-2003 08:32
Note that in version 4.0.3 (the only version I tested):
max (0, 0); // returns 0.
max (0, false); // returns 0.
max (false, 0); // returns false.
max (false, false); // returns false.
As a solution use this:
(int) max (false, 0); // returns 0.
(int) max (false, false); // returns 0.