数组 函数
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array_count_values

(PHP 4, PHP 5)

array_count_values — 统计数组中所有的值出现的次数

说明

array array_count_values ( array $input )

array_count_values() 返回一个数组，该数组用 input 数组中的值作为键名，该值在 input 数组中出现的次数作为值。

Example #1 array_count_values() 例子

<?php
$array = array(1, "hello", 1, "world", "hello");
print_r(array_count_values ($array));
?>

以上例程会输出：

Array
(
    [1] => 2
    [hello] => 2
    [world] => 1
)

参见 count()，array_unique()，array_values() 和 count_chars()。

参数

input

The array of values to count

返回值

Returns an associative array of values from input as keys and their count as value.

错误/异常

Throws E_WARNING for every element which is not string or integer.

范例

Example #2 array_count_values() example

<?php
$array = array(1, "hello", 1, "world", "hello");
print_r(array_count_values($array));
?>

以上例程会输出：

Array
(
    [1] => 2
    [hello] => 2
    [world] => 1
)

参见

数组 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 统计数组中所有的值出现的次数

用户评论:

muhamed dot pasha at gmail dot com (15-Dec-2010 08:56)

Hy,

i had a problem which was associated with the array_count_values function, but did not solve my problem realy well so i made a function by my self and maybe it can help also someone else.

The problem was that i had a table like this:
CL     PRODNUM        QN      DATE
1    4221110030    2    10.12.2010
2    4221110031    1    10.12.2010
3    5241110002    1    10.12.2010
3    5241110003    1    11.12.2010
3    5241110001    2    11.12.2010
3    6241110001    1    11.12.2010
1    2231110999    1    10.12.2010
1    2231110999    1    11.12.2010
(it go's on and on ... )

And i wanted to calculate for every unique date how much the quantity of the specific CL is.
For example the result should be like this:

10.12.2010: [1] -> 3
10.12.2010: [2] -> 1
10.12.2010: [3] -> 1

11.12.2010: [1] -> 1
11.12.2010: [2] -> 0
11.12.2010: [3] -> 4

So, i had to make a function which should look for unique values of a date and then for that date get the quantity of uniqe CL's.

For note: i put all the values of the table into an array:
<?php
$a = array();
$a['cl'] = 1;
$a['prodnum'] = '4221110030';
$a['qn'] = '2';
$a['date'] = '10.12.2010';
?>

The function looks like this:

<?php

function csav( $array, $distinctV, $searchInV, $sumValue ){

        #result array
    $result = array();
   
    #finding the unique dates
    $array1 = array_unique($array[$searchInV]);
    $array2 = array();
    $unique1 = array_merge($array2, $array1);
   
    #finding the unique CL's
    $array3 = array_unique($array[$distinctV]);
    $array4 = array();
    $unique2 = array_merge($array4, $array3);
   
    #for statements through the unique dates
    for($k = 0; $k < count($unique1); $k++){
   
        for($i = 0; $i < count($unique2); $i++){
       
            $sum = 0;
            for($j = 0; $j < count($array[$distinctV]); $j++){
           
                if($array[$distinctV][$j] == $unique2[$i] and $array[$searchInV][$j] == $unique1[$k])
                    $sum += $array[$sumValue][$j];
            }
            $result[$unique1[$k]][$unique2[$i]] = $sum;
        }
   
    }

    return $result;
}

?>

The use of function has to be like this:

<?php
$result = csav($a, 'cl', 'date', 'qn');
print_r($result);
?>

And the result looks like this:

Array ( [2010-12-10] => Array ( [1] => 14 [2] => 17 [3] => 4 ) [2010-12-13] => Array ( [1] => 13 [2] => 17 [3] => 4 ) [2010-12-14] => Array ( [1] => 13 [2] => 17 [3] => 4 ) [2010-12-15] => Array ( [1] => 14 [2] => 17 [3] => 4 ) [2010-12-16] => Array ( [1] => 14 [2] => 17 [3] => 2 ) )

This is it.
Hope it helps someone.

szczepan.krolgmail.c0m (17-Jan-2010 07:21)

Here is a Version with one or more arrays, which have similar values in it:
Use $lower=true/false to ignore/set case Sensitiv.

<?php

$ar1[] = array("red","green","yellow","blue");
$ar1[] = array("green","yellow","brown","red","white","yellow");
$ar1[] = array("red","green","brown","blue","black","yellow");
#$ar1= array("red","green","brown","blue","black","red","green"); // Possible with one or multiple Array

$res = array_icount_values ($ar1);
print_r($res);

function array_icount_values($arr,$lower=true) {
     $arr2=array();
     if(!is_array($arr['0'])){$arr=array($arr);}
     foreach($arr as $k=> $v){
      foreach($v as $v2){
      if($lower==true) {$v2=strtolower($v2);}
      if(!isset($arr2[$v2])){
          $arr2[$v2]=1;
      }else{
           $arr2[$v2]++;
           }
    }
    }
    return $arr2;
}
/*
Will print:
Array
(
    [red] => 3
    [green] => 3
    [yellow] => 4
    [blue] => 2
    [brown] => 2
    [white] => 1
    [black] => 1
)
*/
?>

bluej100@gmail (25-Mar-2008 09:37)

byron at byronrode dot co dot za, here are some benchmarks.

<?php
$haystack = Array();
for ($i = 0; $i < 1000000; $i++) {
  $haystack[] = rand(1, 2000);
}

$needle = rand(1, 2000);

echo "__array_count_values()__\n";
$start = microtime(true);
$startmem = memory_get_usage();
$counts = array_count_values($haystack);
$mem = memory_get_usage()-$startmem;
echo 'Count:'.$counts[$needle]."\n";
echo 'Time:'.(microtime(true) - $start)."\n";
echo 'Memory:'.$mem."\n\n";

echo "__array_keys()__\n";
$start = microtime(true);
$startmem = memory_get_usage();
$keys = array_keys($haystack, $needle);
$mem = memory_get_usage()-$startmem;
echo 'Count:'.count($keys)."\n";
echo 'Time:'.(microtime(true) - $start)."\n";
echo 'Memory:'.$mem."\n\n";

echo '__$needle_array[]__'."\n";
$start = microtime(true);
$startmem = memory_get_usage();
$x = count($haystack);
for($i = 0; $i < $x; $i++){
  if($haystack[$i] == $needle){
    $needle_array[] = $haystack[$i];
  }
}
$mem = memory_get_usage()-$startmem;
$number_of_instances = count($needle_array);
echo 'Count:'.$number_of_instances."\n";
echo 'Time:'.(microtime(true) - $start)."\n";
echo 'Memory:'.$mem."\n\n";

echo '__$number_of_instances++__'."\n";
$start = microtime(true);
$startmem = memory_get_usage();
$x = count($haystack);
$number_of_instances = 0;
for($i = 0; $i < $x; $i++){
  if($haystack[$i] == $needle){
    $number_of_instances++;
  }
}
$mem = memory_get_usage()-$startmem;
echo 'Count:'.$number_of_instances."\n";
echo 'Time:'.(microtime(true) - $start)."\n";
echo 'Memory:'.$mem."\n\n";
?>

[www]mytemp$ php array_count_test.php
__array_count_values()__
Count:515
Time:0.0607650279999
Memory:120328

__array_keys()__
Count:515
Time:0.0869138240814
Memory:33016

__$needle_array[]__
Count:515
Time:0.259949922562
Memory:24792

__$number_of_instances++__
Count:515
Time:0.258481025696
Memory:0

However, when you use an array of strings by calling md5(rand(1, 2000)), the performance boosts become less significant:

__array_count_values()__
Count:499
Time:0.491794109344
Memory:184328

__array_keys()__
Count:499
Time:0.36399102211
Memory:30072

__$needle_array[]__
Count:499
Time:0.568728923798
Memory:22104

__$number_of_instances++__
Count:499
Time:0.574353933334
Memory:0

Results are similar for string->string haystacks with foreach traversal.

Hayley Watson (13-Mar-2008 07:37)

Yet Another case-insensitive version of array_count_values()

<?php
$ar = array('J. Karjalainen', 'J. Karjalainen', 60, '60', 'J. Karjalainen', 'j. karjalainen', 'Fastway', 'FASTWAY', 'Fastway', 'fastway', 'YUP');

$ar = array_count_values(array_map('strtolower', $ar));
?>

byron at byronrode dot co dot za (26-Jun-2007 01:19)

I am building a script for a quiz, and could not find any answers to count the number of times a value was repeated in an array, and came up with the following function.

<?php

// Answers Array
$array = array('a', 'b', 'a', 'a', 'c', 'a', 'd', 'a', 'c', 'd');

// Start Count Function
function count_repeat_values($needle, $haystack){
   
    $x = count($haystack);
   
    for($i = 0; $i < $x; $i++){
       
        if($haystack[$i] == $needle){
            $needle_array[] = $haystack[$i];
        }
    }
   
    $number_of_instances = count($needle_array);
   
    return $number_of_instances;
}

echo count_repeat_values('a', $array);

// will return the value 5
?>

But after writing the function, I happened to stroll upon array_count_values() which I had completely forgotten about.

I know that i could get the value by doing this:

<?php

$array = array('a', 'b', 'a', 'a', 'c', 'a', 'd', 'a', 'c', 'd');

$answer = array_count_values($array);
echo $answer['a']

?>

Would be interesting to see which version works quicker...

majerm at gmail dot com (18-Jun-2007 03:50)

<?
function array_icount_values($array) {
    $ret_array = array();
    foreach($array as $value) $ret_array[strtolower($value)]++;
    return $ret_array;
}

$ar = array('J. Karjalainen', 'J. Karjalainen', 60, '60', 'J. Karjalainen', 'j. karjalainen', 'Fastway', 'FASTWAY', 'Fastway', 'fastway', 'YUP');
$ar = array_icount_values($ar);
?>

this prints:

Array
(
    [j. karjalainen] => 4
    [60] => 2
    [fastway] => 4
    [yup] => 1
)

rabies dot dostojevski at gmail dot com (21-Feb-2007 09:40)

I couldn't find a function for counting the values with case-insensitive matching, so I wrote a quick and dirty solution myself:

<pre><?php
function array_icount_values($array) {
    $ret_array = array();
    foreach($array as $value) {
        foreach($ret_array as $key2 => $value2) {
            if(strtolower($key2) == strtolower($value)) {
                $ret_array[$key2]++;
                continue 2;
            }
        }
        $ret_array[$value] = 1;
    }
    return $ret_array;
}

$ar = array('J. Karjalainen', 'J. Karjalainen', 60, '60', 'J. Karjalainen', 'j. karjalainen', 'Fastway', 'FASTWAY', 'Fastway', 'fastway', 'YUP');
$ar2 = array_count_values($ar); // Normal matching
$ar = array_icount_values($ar); // Case-insensitive matching
print_r($ar2);
print_r($ar);
?></pre>

This prints:

Array
(
    [J. Karjalainen] => 3
    [60] => 2
    [j. karjalainen] => 1
    [Fastway] => 2
    [FASTWAY] => 1
    [fastway] => 1
    [YUP] => 1
)
Array
(
    [J. Karjalainen] => 4
    [60] => 2
    [Fastway] => 4
    [YUP] => 1
)

I don't know how efficient it is, but it seems to work. Needed this function in one of my scripts and thought I would share it.

meyermagic at gmail dot com (17-Jan-2007 02:43)

Scratch that, I did something stupid. Here is a better function.

<?php
    function array_enumerate_keys($array)
    {
        $index = 0;
        $enumerated = array();
        $values = array_values($array);
        $keys = array_keys($array);
        for($index = 0; $index < count($array); $index++)
        {
            $iteration;
            for($iteration = 0; $iteration < $values[$index]; $iteration++)
            {
                $enumerated = array_merge($enumerated, array($keys[$index]));
            }
        }
       
        return $enumerated;
    }
?>

meyermagic at gmail dot com (16-Jan-2007 10:58)

A possible inverse function for array_count_values

<?php
    function array_enumerate_keys($array)
    {
        $index;
        $enumerated;
        $values = array_values($array);
        $keys = array_keys($array);
        for($index = 0; $index < count($array); $index++)
        {
            $iteration;
            for($iteration = 0; $iteration < $values[$index]; $iteration++)
            {
                $enumerated .= $keys[$index] . ',';
            }
        }
       
        return explode(',', $enumerated);
    }
?>

coda at bobandgeorge dot com (14-Oct-2005 01:52)

alwaysdrunk's comment only works if you can trust the client web browser. Using this function doesn't validate that every necessary field exists -- only that every field that was submitted has a value in it. Thus if an attacker wished to force a null value into one of the fields, he could (rather easily) construct a modified form without the field and submit THAT.

Besides, you really ought to be validating each field anyway if you're taking user input.

alwaysdrunk at gmail com (12-May-2005 08:14)

if you have too many values in $_POST,$_GET array that needs to be controlled with isset() in oreder to understand the form is filled completely and have no empty text boxes.
you can try this,it saves time.

<?
$n = array_count_values($_POST);
if (!isset($n[''])) {
echo "The form is filled completely";
}
else
{ die("Please fill the form comlpetely"); }

//tested in php 5
?>

[Mr.A] (06-Mar-2005 10:59)

I find a very simple solution to count values in multidimentional arrays (example for 2 levels) :

foreach ($array as $a) {
  foreach ($a as $b) {
    $count_values[$b]++;
  }
}

blauauge at figh7club dot com (04-Sep-2003 05:12)

my solution for count  on multidimentional arrays.

<?php
  for($i = 0; $i < count($array); $i++) {
      $detail = explode("|", $array[$i]);
      echo "$i - $detail[0] - $detail[1]<br><br>";
      if($detail[1] == '1') { $wieoft1 = $wieoft1 +=1; }
      if($detail[1] == '2') { $wieoft2 = $wieoft2 +=1; }
      if($detail[1] == '3') { $wieoft3 = $wieoft3 +=1; }
  }
  echo ". $wieoft1 : $wieoft2 : $wieoft3";
?>

looks not pretty fine yet works great for me.
make it bigger for your own.

programmer at bardware dot de (19-Aug-2003 07:24)

array_count_values returns the number of keys if empty(value). I expected array_count_values to return 0 for empty values.

Array looks like:
Array
        (
            [459] =>
            [543] =>
            [8959] =>
            [11273] =>
        )

array_count_values returns:
Array
(
    [] => 4
)

count(array_count_values(array)) does thus not report there are no values (other than empty) in the array.

I therefore check:
$arrFoo=array_count_values($arrBar);
if(isset($arrFoo[""]) $allempty=count($arrBar)==$arrFoo[""];
if(!$allempty)
//process the array
else
//no need to work on the array

digleu at codeway dot de (28-May-2003 10:58)

I fount a solution for the count of array elements in the sense of array_count_values, but i was not able to use the function array_count_values itself because it does not say me if arrays exists in the given array, so i had to use a foreach loop and a little bit of recursivity ;)

<?php
function array_count_values_multidim($a,$out=false) {
  if ($out===false) $out=array();
  if (is_array($a)) {
    foreach($a as $e)
      $out=array_count_values_multidim($e,$out);
  }
  else {
    if (array_key_exists($a,$out))
      $out[$a]++;
    else
      $out[$a]=1;
  }
  return $out;
}
?>

pmarcIatIgeneticsImedIharvardIedu (30-Jan-2003 01:42)

array_count_values function does not work on multidimentional arrays.
If $score[][] is a bidimentional array, the command
"array_count_values ($score)" return the error message "Warning: Can only count STRING and INTEGER values!".

manuzhai (AT) php (DOT) net (16-Nov-2002 02:45)

You might use serialize() to serialize your objects before analyzing their frequency. :)

jon at fuck dot org (14-Aug-2002 10:31)

suggested plan of attack:

<pre>
<?
class MyObject {
    function MyObject($t = 'none')
    {
      $this->$myTag = $t;
    }
}

$myArray = array();

for ($i = 1 ; $i < 11 ; $i++)
{
   $myobj = new MyObject( str_pad('n', $i, 'x') );
   $myArray[ $myobj->$myTag ] = $myobj;
}

print_r( array_count_values(array_keys($myArray)) );
?>

to sum up:
assuming each instance of an object you create has some sort of tag, e.g.,

$this->$myTag=get_class($this)

..you should be set. objects dont have value to compare the way strings and integers do, so, $myTag's value is arbitrary.

tschneider at formel4 dot de (12-Jun-2002 03:09)

This does not works with objects. If you have an array filled with objects, you can not count them.

Example:

<?php
$myArray = array();
for ($i = 0 ; $i < 10 ; $i++)
{
   $myObject = new MyObject();
   $myArray[$i] = $myObject;
}

echo (array_count_values($myArray));
?>

This gives you:
Warning: Can only count STRING and INTEGER values...

Found no solution for this yet...