array_count_values

(PHP 4, PHP 5)

array_count_valuesConta tutti i valori di un array

Descrizione

array array_count_values ( array $input )

array_count_values() restituisce un array che ha i valori dell'array input per chiavi e la loro frequenza in input come valori.

Example #1 Esempio di array_count_values()

<?php
$array 
= array(1"ciao"1"mondo""ciao");
print_r(array_count_values($array));
?>

Il precedente esempio visualizzerà:

Array
(
    [1] => 2
    [ciao] => 2
    [mondo[ => 1
)

Vedere anche count(), array_unique(), array_values() e count_chars().

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User Contributed Notes 11 notes

up
15
[Mr.A]
9 years ago
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]++;
  }
}
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3
majerm at gmail dot com
6 years ago
<?
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
)
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1
pmarcIatIgeneticsImedIharvardIedu
11 years ago
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!".
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1
Hayley Watson
6 years ago
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));
?>
up
1
jakubplus at gmail dot com
13 days ago
In order to apply array_map with callback checking for localised values like city name, country name, you have to provide some sort of comparison array.

Here's an example of array_count_values for Polish city names. Just switch array_keys / array_values in order to obtain lowercase / uppercase.

$arr = array('Warsaw', 'Warsaw', 'Wrocław', 'Poznań', 'KrakÓw', 'waRsaw', 'Gdańsk', 'poznań', 'WROCŁAW', 'kraków', 'GDAŃSK');
$lowertoupperpolish = array(
    'ą' => 'Ą',
    'ć' => 'Ć',
    'ę' => 'Ę',
    'ł' => 'Ł',
    'ń' => 'Ń',
    'ó' => 'Ó',
    'ś' => 'Ś',
    'ż' => 'Ż',
    'ź' => 'Ź',
);
function lowers($n) {
    global $lowertoupperpolish;
    return strtolower(str_replace(array_values($lowertoupperpolish), array_keys($lowertoupperpolish), $n));
}
$result = array_count_values(array_map('lowers', $arr));

print_r($result); ...prints:

Array ( [warsaw] => 3 [wrocław] => 2 [poznań] => 2 [kraków] => 2 [gdańsk] => 2 )
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0
Dominic Vonk
4 months ago
The case-insensitive version:

<?php
function array_count_values_ci($array) {
   
$newArray = array();
    foreach (
$array as $values) {
        if (!
array_key_exists(strtolower($values), $newArray)) {
           
$newArray[strtolower($values)] = 0;
        }
       
$newArray[strtolower($values)] += 1;
    }
    return
$newArray;
}
?>
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0
szczepan.krolgmail.c0m
4 years ago
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
)
*/
?>
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0
rabies dot dostojevski at gmail dot com
7 years ago
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.
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-2
bluej100@gmail
6 years ago
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.
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-3
coda at bobandgeorge dot com
8 years ago
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.
up
-4
manuzhai (AT) php (DOT) net
11 years ago
You might use serialize() to serialize your objects before analyzing their frequency. :)
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