min

(PHP 4, PHP 5, PHP 7, PHP 8)

min找出最小值

说明

min(mixed $value, mixed ...$values): mixed

替代签名(不支持命名参数):

min(array $value_array): mixed

如果仅有一个参数且为数组,min() 返回该数组中最小的值。如果给出了两个或更多参数, min() 会返回这些值中最小的一个。

注意:

不同类型的值将使用标准比较规则进行比较。例如,一个非数字 stringint 比较时就当做是 0,但多个非数字 string 值将会按照字母数字比较。返回的实际值是未应用任何转换的原始类型。

警告

传递不同类型的参数时要小心,因为 min() 会产生不可预测的结果。

参数

value

任何可比较的值。

values

任何可比较的值。

value_array

包含值的数组。

返回值

max() 根据标准比较返回认为是“最小”的参数值。如果不同类型的多个值认为相等(比如 0'abc'),则将会返回提供给函数的第一个值。

错误/异常

如果传递空数组,max() 抛出 ValueError

更新日志

版本 说明
8.0.0 min() 现在失败时会抛出 ValueError;之前会返回 false 并发出 E_WARNING 错误。

范例

示例 #1 min() 用法的例子

<?php
echo min(2, 3, 1, 6, 7); // 1
echo min(array(2, 4, 5)); // 2

// The string 'hello' when compared to an int is treated as 0
// Since the two values are equal, the order they are provided determines the result
echo min(0, 'hello'); // 0
echo min('hello', 0); // hello

// Here we are comparing -1 < 0, so -1 is the lowest value
echo min('hello', -1); // -1

// With multiple arrays of different lengths, min returns the shortest
$val = min(array(2, 2, 2), array(1, 1, 1, 1)); // array(2, 2, 2)

// Multiple arrays of the same length are compared from left to right
// so in our example: 2 == 2, but 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,则绝对不会返回数组
// 因为比较认为数组大于任何值
$val = min('string', array(2, 5, 7), 42); // string

// If one argument is NULL or a boolean, it will be compared against
// other values using the rules FALSE < TRUE and NULL == FALSE regardless of the
// other types involved
// In the below examples, both -10 and 10 are treated as TRUE in the comparison
$val = min(-10, FALSE, 10); // FALSE
$val = min(-10, NULL, 10); // NULL

// 0, on the other hand, is treated as FALSE, so is "lower than" TRUE
$val = min(0, TRUE); // 0
?>

参见

  • max() - 找出最大值
  • count() - 统计数组、Countable 对象中所有元素的数量

add a note

User Contributed Notes 17 notes

up
4
volch5 at gmail dot com
8 years ago
min() (and max()) 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
Anonymous
17 years ago
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 !
up
0
Teelevision
9 years ago
A function that returns the lowest integer that is not 0.
<?php
/* like min(), but casts to int and ignores 0 */
function min_not_null(Array $values) {
    return
min(array_diff(array_map('intval', $values), array(0)));
}
?>
up
-1
DO
14 years ago
I've modified the bugfree min-version to ignore NULL values (else it returns 0).

<?php
function min_mod () {
 
$args = func_get_args();

  if (!
count($args[0])) return false;
  else {
   
$min = false;
    foreach (
$args[0] AS $value) {
      if (
is_numeric($value)) {
       
$curval = floatval($value);
        if (
$curval < $min || $min === false) $min = $curval;
      }
    }
  }

  return
$min;  
}
?>
up
-3
harmor
14 years ago
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
up
-3
hava82 at gmail dot com
11 years ago
Here is function can find min by array key

<?php
function min_by_key($arr, $key){
   
$min = array();
    foreach (
$arr as $val) {
        if (!isset(
$val[$key]) and is_array($val)) {
           
$min2 = min_by_key($val, $key);
           
$min[$min2] = 1;
        } elseif (!isset(
$val[$key]) and !is_array($val)) {
            return
false;
        } elseif (isset(
$val[$key])) {
           
$min[$val[$key]] = 1;
        }
    }
    return
min( array_keys($min) );
}
?>
up
-3
steffen at morkland dot com
16 years ago
> 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 ===
up
-5
8ilO
5 years ago
A min_by function:
<?php
function min_by(Array $arr, Callable $func){
   
$mapped = array_map($func, $arr);
    return
$arr[array_search(min($mapped), $mapped)];
}
$a = ["albatross""dog""horse"];
echo
min_by($a, "strlen"); // dog
?>
up
-4
johnphayes at gmail dot com
16 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
-4
piotr_sobolewski at o2 dot nospampleasenono dot pl
15 years ago
Be very careful when your array contains both strings and numbers. This code works strange (even though explainable) way:
var_dump(max('25.1.1', '222', '99'));
var_dump(max('2.1.1', '222', '99'));
up
-5
matt at borjawebs dot com
12 years ago
A condensed version (and possible application) of returning an array of array keys containing the same minimum value:

<?php
// data
$min_keys = array();
$player_score_totals = array(
'player1' => 300,
'player2' => 301,
'player3' => 302,
'player4' => 301,
...
);

// search for array keys with min() value
foreach($player_score_totals as $playerid => $score)
    if(
$score == min($player_score_totals)) array_push($min_keys, $playerid);

print_r($min_keys);
?>
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-7
php at keith tyler dot com
12 years ago
If NAN is the first argument to min(), the second argument will always be returned.

If NAN is the second argument, NAN will always be returned.

The relationship is the same but inverted for max().

<?php
// \n's skipped for brevity
print max(0,NAN);
print
max(NAN,0);
print
min(0,NAN);
print
min(NAN,0);
?>

Returns:
0
NAN
NAN
0
up
-7
alx5000 at walla dot com
18 years ago
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
?>
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-6
nonick AT 8027 DOT org
19 years ago
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.
up
-10
Err
13 years ago
When using a variable with an array that has a list of numbers, put just the variable in min(). Don't use integer index's. Seems pretty straight forward now, but I wasn't used to just putting down the variable for an array in functions.

<?php
  $list
= array(9,5,4,6,2,7);
  echo
min($list); // display 2
?>
up
-14
browne at bee why you dot ee dee you
19 years ago
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);
up
-15
dave at dtracorp dot com
16 years ago
empty strings '' will also return false or 0, so if you have something like

$test = array('', 1, 5, 8, 44, 22);

'' will be returned as the lowest value

if you only want to get the lowest number, you'll have to resort to the old fashioned loop

// default minimum value
$minVal = 100;
foreach ($test as $value) {
if (is_numeric($value) && $value < $minVal) {
$minVal = $value;
}
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