min

说明

mixed min ( number arg1, number arg2 )

mixed min ( array numbers [, array ...] )

min() 返回参数中数值最小的。

如果仅有一个参数且为数组，min() 返回该数组中最小的值。如果第一个参数是整数、字符串或浮点数，则至少需要两个参数而 min() 会返回这些值中最小的一个。可以比较无限多个值。

注: PHP 会将非数值的 string 当成 0，但如果这个正是最小的数值则仍然会返回一个字符串。如果多个参数的值都是 0，min() 将返回第一个（最左边的值）。

例子 1. 使用 min() 的例子
<?php echo min(2, 3, 1, 6, 7); // 1 echo min(array(2, 4, 5)); // 2 echo min(0, 'hello'); // 0 echo min('hello', 0); // hello echo min('hello', -1); // -1 // 对多个数组，min 从左向右比较。 // 因此在本例中：2 == 2，但 4 < 5 $val = min(array(2, 4, 8), array(2, 5, 1)); // array(2, 4, 8) // 如果同时给出数组和非数组作为参数，则不可能返回数组，因为 // 数组被视为最大的 $val = min('string', array(2, 5, 7), 42); // string ?>

参见 max() 和 count()。

add a note User Contributed Notes

johnphayes at gmail dot com
03-May-2006 12:26


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

steffen at morkland dot com
16-Mar-2006 06:16


> NEVER EVER use this function with boolean variables !!!

> Or you'll get something like this: min(true, 1, -2) == true;



> Just because of:

> min(true, 1, -2) == min(min(true,1), -2) == min(true, -2) == true;



It is possible to use it with booleans, there is is just one thing, which you need to keep in mind, when evaluating using the non strict comparison (==) anyting that is not bool false, 0 or NULL is consideret true eg.:

(5 == true) = true;

(0 == true) = false;

true is also actually anything else then 0, false and null. However when true is converted to a string or interger true == 1, therefore when sorting true = 1. But if true is the maximum number bool true is returned. so to be sure, if you only want to match if true is the max number remember to use the strict comparison operater ===

01-Feb-2006 01:37


NEVER EVER use this function with boolean variables !!!

Or you'll get something like this: min(true, 1, -2) == true;



Just because of:

min(true, 1, -2) == min(min(true,1), -2) == min(true, -2) == true;



You are warned !

DASPRiD d [AT] sprid [DOT] de
06-Jul-2005 09:39


Here is my slightly modified version of the bugfree min-version. Now the max() function is no longer used in the modification and overall it's fasten up. Would be nice to get some feedback.



<?php

function min_mod () {

  $args = func_get_args();

  

  if (!count($args)) return false;

  else {

    $min = false;

    foreach ($args AS $value) {

      $curval = floatval($value);

      if ($curval < $min || $min === false) $min = $curval;

    }

  }

  

  return $min;    

}

?>

alx5000 at walla dot com
13-Jan-2005 09:16


If you want min to return zero (0) when comparing to a string, try this:



<?php

min(3,4,";");  // ";"

min(0,min(3,4,";")) // 0

?>

nonick AT 8027 DOT org
24-Jan-2004 11:43


I tested this with max(), but I suppose it applies to min() too: If you are working with numbers, then you can use:

 

    $a = ($b < $c) ? $b : $c;

 

 which is somewhat faster (roughly 16%) than

 

    $a = min($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.

browne at bee why you dot ee dee you
17-Dec-2003 06:30


min() can be used to cap values at a specific value. For instance, if you're grading papers and someone has some extra credit, but  that shouldn't make it to the final score:



$pts_possible = 50;

$score = 55;



// Percent will equal 1 if $score/$pts_possible is greater than 1

$percent = min($score/$pts_possible,1);

kieran at mgpenguin dot net
19-Jul-2003 11:28


Further modifications to the minnum function above.. This is for a project where I had to grab an entire column out of a database consisting of values that might be string, might be string representations of numbers (floating point or integer) or might be NULL, and find the minimum NUMERIC value:



function minnum($numarray){

    //dont use min(), it contains a bug!

    $min=0;

    if ( ! is_array($numarray) ) $numarray = func_get_args();

    if(is_array($numarray)==true){

        $min=max($numarray);

        for($z=0;$z<count($numarray);$z++){

            $curval=floatval($numarray[$z]);

            if(($curval != 0) && ($curval < $min)){

                $min=$curval;

            }

        }

    }

    return $min;

}



Gets the floating point value of each entry and uses this to check whether it's actually a number before checking whether it's the minimum or not. Also contains modifications noted above to use it as a drop in replacement for min - ie multiple values passed.

Merome at wanadoo dot fr
06-Jul-2003 12:40


Caution : it seems that min() can return a string : 



min(";",50)=";" (I expected zero)

calin at php9 dot com
30-May-2003 11:19


if you have an array like this



$arSrc[0]=14;

$arSrc[1]=16;

$arSrc[2]=13;

$arSrc[3]=17;



then in order to get the min element and its position in the array you can do:



$iMinValue = min($arSrc);

$arFlip = array_flip($arSrc);

$iMinPosition = $arFlip[$iMinValue];



echo 

 '<br />min_value=',

 $iMinValue,

 '<br />min_position=',

 $iMinPosition

;



this example works for also for an associative array; of course with numeric values

09-Jul-2002 05:36


Re: above example - for a proper drop in replacement for the above, insert



if ( ! is_array($numarray) )

   $numarray = func_get_args();



after

   $min=0;



(For PHP3, check 

if (intval(PHP_VERSION) >= 4 && ! is_array($numarray)) 

   $numarray = func_get_args();

)

kevin at pricetrak dot com
09-Apr-2002 02:47


The 'undefined' behaviour can bit you badly. I would expect min(undefined, -1000) to return -1000. Not so.

nak2 at mail2000 dot ru
15-Mar-2002 03:36


If one of elements is undefided, min() result is underfinded too

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