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array_count_values — 统计数组中所有的值出现的次数
$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。
input
统计这个数组的值
返回一个关联数组,用 input
数组中的值作为键名,该值在数组中出现的次数作为值。
对数组里面的每个不是 string 和 integer 类型的元素抛出一个警告错误( E_WARNING
)。
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 )
[#1] jakubplus at gmail dot com [2014-04-07 11:36:17]
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', 'Wroc?aw', 'Pozna??', 'Krak?w', 'waRsaw', 'Gda??sk', 'pozna??', 'WROC?AW', 'krak??w', 'GDA?SK');
$lowertoupperpolish = array(
'?' => '?',
'?' => '?',
'?' => '?',
'?' => '?',
'??' => '?',
'??' => '?',
'?' => '?',
'?' => '?',
'?' => '?',
);
function lowers($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 [wroc?aw] => 2 [pozna??] => 2 [krak??w] => 2 [gda??sk] => 2 )
[#2] Dominic Vonk [2013-12-13 16:11:01]
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;
}
?>
[#3] szczepan.krolgmail.c0m [2010-01-17 11:21:19]
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;
}
?>
[#4] bluej100@gmail [2008-03-25 13:37:13]
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.
[#5] Hayley Watson [2008-03-13 11:37:16]
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', $ar));
?>
[#6] majerm at gmail dot com [2007-06-18 07:50:30]
<?php
function array_icount_values($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
)
[#7] rabies dot dostojevski at gmail dot com [2007-02-21 01:40:15]
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
</pre>
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);
?>
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.
[#8] coda at bobandgeorge dot com [2005-10-14 05:52:25]
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.
[#9] [Mr.A] [2005-03-06 02:59:17]
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]++;
}
}
[#10] pmarcIatIgeneticsImedIharvardIedu [2003-01-29 17:42:45]
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!".
[#11] manuzhai (AT) php (DOT) net [2002-11-16 06:45:56]
You might use serialize() to serialize your objects before analyzing their frequency. :)