compact
The code snippet posted by legobuff at hotmail dot com on 02-Feb-2000 contains an error. This is the code that was posted:
<?php
// To find the index of the last element in the array:
end($yourArray);
$index = key($yourArray);
?>
However, this will fail if the indices have been stored out of sequence. What you actually want is max(array_keys($yourArray)), as indicated below:
<?php
$yourArray = array(1=>'a', 7=>'b', 5=>'c');
print count($yourArray); // prints 3
end($yourArray);
print key($yourArray); // prints 5
print max(array_keys($yourArray)); // prints 7
?>
count
(PHP 4, PHP 5)
count — 배열의 모든 원소나, 객체의 프로퍼티 수를 셉니다
설명
배열의 모든 원소나, 객체의 프로퍼티 수를 셉니다.
객체는 SPL을 설치했다면, Countable 인터페이스를 가질 경우에 count()를 사용할 수 있습니다. 이 인터페이스는 정확히 하나의 메쏘드 count()을 가지며, count() 함수의 반환값을 반환합니다.
매뉴얼 배열 섹션을 참고하여 배열이 PHP에서 어떻게 구현되고 사용되는지 확인하십시오.
인수
- var
-
배열.
- mode
-
선택적인 mode 인수를 COUNT_RECURSIVE(또는 1)로 설정하면, count()는 배열을 재귀적으로 셉니다. 이는 다차원 배열의 원소를 셀 경우 유용한 경우가 있습니다. mode 기본값은 0입니다. count()는 무한 재귀를 검출하지 못합니다.
반환값
var 안에 있는 원소 수를 반환합니다. 보통 array이며, 다른 자료형은 하나의 요소만 가집니다.
var 가 배열이나 Countable 인터페이스를 가진 객체가 아니라면, 1을 반환합니다. 한가지 예외는, var 가 NULL일 경우에 0을 반환합니다.
Caution
count()는 설정하지 않은 변수에 대하여 0을 반환하지만, 빈 배열에 대해서도 0을 반환합니다. 변수를 설정했는지 여부는 isset()을 사용하시오.
| 버전 | 설명 |
|---|---|
| 4.2.0 | 선택적인 mode 인수가 추가되었습니다. |
예제
Example #1 count() 예제
<?php
$a[0] = 1;
$a[1] = 3;
$a[2] = 5;
$result = count ($a);
// $result == 3
$b[0] = 7;
$b[5] = 9;
$b[10] = 11;
$result = count ($b);
// $result == 3;
$result = count(null);
// $result == 0
$result = count(false);
// $result == 1
?>
Example #2 재귀적인 count() 예제
<?php
$food = array( 'fruits' => array('orange', 'banana', 'apple'),
'veggie' => array('carrot', 'collard','pea'));
// 재귀 count
echo count($food,COUNT_RECURSIVE); // 8 출력
// 보통 count
echo count($food); // 2 출력
?>
add a note
User Contributed Notescount
ravenswd at gmail dot com
04-Aug-2009 07:37
04-Aug-2009 07:37
jezdec at email dot cz
19-Apr-2009 11:42
19-Apr-2009 11:42
Hi there,
there is a simple script with example for counting rows and columns of a two-dimensional array.
<?php
$data = array(
"apples" =>
array("red", "yellow", "pineapples"),
"bananas" =>
array("small", "medium", "big"),
"vegs" =>
array("potatoes", "carrots", "onions")
);
$rows = count($data,0);
$cols = (count($data,1)/count($data,0))-1;
print "There are {$rows} rows and {$cols} columns in the table!";
?>
michael.debyl at gmail dot comz0r
16-Jul-2008 10:45
16-Jul-2008 10:45
There doesn't seem to be a succinct method already noted on this page for counting multidimensional array end nodes (Items in multidimensional arrays), so I thought this function might help somebody.
Nice and simple :)
<?php
function rcount ($array) {
$count = 0;
if (is_array($array)) {
foreach($array as $id=>$sub) {
if (!is_array($sub)) { $count++; }
else { $count = ($count + rcount($sub)); }
}
return $count;
}
return FALSE;
}
?>
analpaper{gmail}
04-Jul-2008 02:37
04-Jul-2008 02:37
I found useful this little function that detects if a array is multidimensional or not.
<?php
function array_is2D($array) {
return is_array($array) ? count($array)===count($array, COUNT_RECURSIVE) : -1;
}
?>
---
live2code
Anonymous
11-Jan-2008 09:20
11-Jan-2008 09:20
Here is an iterative soloution of danny's count_recursive function which might be more efficient due to the missing recursion
<?php
/**
* counts elements of an multidimensional array
*
* @param array $array Input Array
* @param int $limit dimensions that shall be considered (-1 means no limit )
* @return int counted elements
*/
function multicount ($array, $limit = -1)
{
$cnt = 0;
$limit = $limit > 0 ? (int) $limit : -1;
$arrs[] = $array;
for ($i=0; isset($arrs[$i]) && is_array($arrs[$i]); ++$i)
{
foreach ($arrs[$i] as $value)
{
if (!is_array($value) ) ++$cnt;
elseif( $limit==-1 || $limit>1 )
{
if( $limit>1 ) --$limit;
$arrs[] = $value;
}
}
}
return $cnt;
}
?>
atoi_monte at hotmail dot com
28-Jun-2007 09:10
28-Jun-2007 09:10
Please note: While SPL is compiled into PHP by default starting with PHP 5, the Countable interface is not available until 5.1
danny at dannymendel dot com
13-Jun-2007 08:14
13-Jun-2007 08:14
I actually find the following function more useful when it comes to multidimension arrays when you do not want all levels of the array tree.
// $limit is set to the number of recursions
<?php
function count_recursive ($array, $limit)
{
foreach ($array as $id => $_array)
{
if (is_array ($_array) && $limit > 0) $count += count_recursive ($_array, $limit - 1); else $count += 1;
}
return $count;
}
?>
yarolan at mail dot ru
26-Apr-2007 11:56
26-Apr-2007 11:56
NEVER USE IN CYCLES!
<?php
//size of $arr ~ 2000 elements
//wrong variant (Time exec ~ 19 sec)
for($i=0;$i<count($arr);$i++)
{
//...
}
//right variant(Time exec ~ 0.2 sec)
$arr_size=count($arr);
for($i=0;$i<$arr_size;$i++)
{
//...
}
?>
it was discovered experimentally.
Colin
03-Feb-2007 03:24
03-Feb-2007 03:24
<?php
// countValuesRecursive
// The goal of this function is to count non-false values of a multidimenional array
// This is useful in making a quick determination if a form sent any values
// If no values were sent I can simply return to the blank form rather than continuing to the validation of each input
// There are two limitations of the principle:
// 1. If you WANT to send FALSE, 0, '', or NULL as form values this function will not count those, thus not doing what's expected
// 2. This would create an endless loop on a form that has no required fields such as one where users can choose to recieve optional email subscriptions but where choosing none is also valid
function countValuesRecursive($array, $count = 0) {
// Cycle through the array
foreach ($array as $value) {
// Check if the value is an array
if (is_array($value)) {
// Cycle through deeper level
$count = countValuesRecursive($value, $count);
}
else {
// Check if the value is TRUE
if ($value) {
$count++;
}
}
}
// Return the count
return $count;
}
?>
alexandr at vladykin dot pp dot ru
08-Nov-2006 12:28
08-Nov-2006 12:28
My function returns the number of elements in array for multidimensional arrays subject to depth of array. (Almost COUNT_RECURSIVE, but you can point on which depth you want to plunge).
<?php
function getArrCount ($arr, $depth=1) {
if (!is_array($arr) || !$depth) return 0;
$res=count($arr);
foreach ($arr as $in_ar)
$res+=getArrCount($in_ar, $depth-1);
return $res;
}
?>
anil dot iitk at gmail dot com
26-Jan-2006 08:32
26-Jan-2006 08:32
<?php
$food = array('fruits' => array('orange', 'banana', 'apple'),
'veggie' => array('carrot', 'collard', 'pea'));
// recursive count
echo "<br>".count($food, COUNT_RECURSIVE); // output 8
function average($a){
return array_sum($a)/count($a) ;
}
$b = array(1,2,3,4,5,6,7,8,9);
echo "Average of array:".average($b);
?>
Scorch at netpix dot com
20-Dec-2005 01:59
20-Dec-2005 01:59
Be careful of recasting your variables, especially with database array returns:
<?php
$res = mysql_query("select * from blah") // a query that returns an empty set
$row = mysql_fetch_array($res); // get's 0 since there's no return
echo count($row); // echos 1 - since $row is not an array
echo $row[0]; // echos "", but casts $row as an array?
echo count($row); // echos 0 now
?>
Tom
01-Dec-2005 12:57
01-Dec-2005 12:57
You can find an average from an array using this and array_sum.
<?php
//array average( array input )
function average($input) {
return array_sum($input) / count($input);
}
?>
You can also do a method of form validation that involves putting all errors into an array and letting count() do the key part.
<?php
if(isset($_POST['submit'])) {
$errors = array();
if(empty($_POST['message'])) $errors[] = "Empty message field";
if(!preg_match('/[a-z0-9.]@[a-z0-9].[a-z]/i', $_POST['email']) {
$errors[] = "Bad email address";
}
if(count($errors) == 0) {
//process form...
}
}
?>
Fred D
18-Oct-2005 04:16
18-Oct-2005 04:16
The trim_text function was helpful, but it did not take account of the possibility of having nothing to trim which can sometimes happen if you are using this function in a loop through data. I've added a count function to deal with that possibility
<?php
function trim_text_elipse($text, $count){
//Create variable
$trimmed="";
//Remove double white space
$text = str_replace(" ", " ", $text);
//Turn the text into an array
$string = explode(" ", $text);
//Check to see how many words there are
$wordTotal = count($string);
//Check to see if there are more words than the $count variable
if($wordTotal > $count){
//Loop through adding words until the $count variable is reached
for ( $wordCounter = 0; $wordCounter <= $count; $wordCounter++ ){
$trimmed .= $string[$wordCounter];
//Check to and add space or finish with elipse
if ( $wordCounter < $count ){ $trimmed .= " "; }
else { $trimmed .= " …"; }
}
}else{
//Set value returned to the existing value
$trimmed =$text;
}
//Trim off any white space
$trimmed = trim($trimmed);
return $trimmed;
}
?>
david _at_ webgroup _dot_ org
13-Feb-2005 12:30
13-Feb-2005 12:30
While michael at htmlland dot net's code works, I believe it is better to use:
$extension=substr($file,strrpos($file,".")+1);
This doesn't incur the overhead of array handling. I haven't tested it for time functions, but it should work just as well and SHOULD be faster.
freefaler at gmail dot com
20-Nov-2004 01:01
20-Nov-2004 01:01
If you want to count only elements in the second level of 2D arrays.A close to mind note, useful for multidimentional arrays:
<?php
$food = array('fruits' => array('orange', 'banana', 'apple'),
'veggie' => array('carrot', 'collard','pea'));
// recursive count
echo count($food,COUNT_RECURSIVE); // output 8
// normal count
echo count($food); // output 2
// all the fruits and veggies
echo (count($food,COUNT_RECURSIVE)-count($food,0)); //output 6
?>
moazzam at ummah dot org
14-Oct-2004 11:59
14-Oct-2004 11:59
This is an obvious note, but I am writing it any way so other, who did may not have observed this, can take advantage of it too.
When running loops with count conditions, the code runs faster if you first assign the count() value to a variable and use that (instead of using count() directly in a loop condition.
To explain my point better, here is an example:
<?php
for ($i=0; $i<10000; $i++) {
$arr[] = $i;
}
$time11 = microtime_float();
$bf = "";
for ($i=0; $i<count($arr); $i++) {
$bf .= $arr[$i]."\n";
}
$time12 = microtime_float();
$time1 = $time12 - $time11;
print "First: ".$time1."\n";
$time21 = microtime_float();
$l = count($arr);
for ($i=0; $i<$l; $i++) {
$bf .= $arr[$i]."\n";
}
$time22 = microtime_float();
$time2 = $time22 - $time21;
print "Second: ".$time2."\n";
?>
The output from the code above is (when run many times):
First: 0.13001585006714
Second: 0.099159002304077
First: 0.12128901481628
Second: 0.079941987991333
First: 0.18690299987793
Second: 0.13346600532532
As you can see, the second method (which doesnt use count() directly in the loop) is faster than the first method (which uses count() directly in the loop).
BTW: I copied the microtime_float() function from one of the comments in the microtime() section. It just returns time with microseconds as float. Check comments in microtime() for more info.
michael at htmlland dot net
04-Jun-2004 05:30
04-Jun-2004 05:30
I have found on upload scripts or on file manipulation scripts that people can trick a classic file type filter:
example:
<?php
$filename="bob.jpg.wav";
$bits= explode(".",$filename);
$extention= $bits[1];
if($extention == "jpg"){ echo"Not correct"; exit; }
?>
This returns the filename extention as jpg not wav.
One way to change this is to use count() :
example:
<?php
$filename="bob.jpg.wav";
$bits= explode(".",$filename);
$extention= $bits[count($bits) - 1];
if($extention == "jpg"){ echo "Not correct"; exit; }
?>
This returns the filename extention as wav not jpg.
rolandfoxx at yahoo dot com
31-Mar-2004 12:13
31-Mar-2004 12:13
As an addition, any of the array manipulation functions can likewise get count to once again return 0:
<?php
$a = array();
print(count($a)); // prints 0
$a[0] = "foo";
array_shift($a);
print(count($a)); //prints 0
$a[0] = "bar";
array_splice($a, 0, 1);
print(count($a)); //prints 0
?>
admin at lft-muenchen dot de
12-Mar-2003 12:18
12-Mar-2003 12:18
Note:
<?php
print (strlen($a)); // will print 0
$a="";
print (strlen($a)); // will print 1
$a=null;
print (strlen($a)); // will print 1
$a=array();
print (strlen($a)); // will print 0
?>
you can only get an array back to size 0 by using the array() command, not by just setting it to "" or null.
simon at invalid dot com
20-Aug-2002 07:40
20-Aug-2002 07:40
Reminder for using count():
<?php
$ary = array(null, "a", "b", null);
echo count($ary); // count: 4
$ary[10] = "c";
echo count($ary); // count: 5
$ary[15] = null;
echo count($ary); // count: 6
?>
=> NULL is seen as an element in count()
Count 2D array:
<?php
$a2Dary = array(array("a", "b") , array(), "v");
echo count($a2Dary); // count: 3
echo count($a2Dary[0]); //count 2
echo count($a2Dary[1]); // count: 0
echo count($a2Dary[2]); // count: 1
?>
Hope can help you
webmaster at NOSPAMtrafficg dot com
26-Apr-2002 10:48
26-Apr-2002 10:48
Counting a multi-dimentional array
test array
<?php
$settings[0][0] = 128;
$settings[0][1] = 256;
$settings[0][2] = 384;
$settings[0][3] = 512;
$settings[0][4] = 1024;
$settings[0][5] = 2048;
$settings[1][0] = 1024;
$settings[1][1] = 2048;
$settings[1][2] = 3072;
$settings[1][3] = 4096;
count($settings) // returns 2
count($settings[0]) // returns 6
count($settings[1]) // returns 4
?>
kanareykin at denison dot edu
26-Mar-2001 09:13
26-Mar-2001 09:13
Here's how to count non-empty elements
in an array of any dimension. Hope
it will be useful for somebody.
<?php
// recursively count all non-empty elements
// in array of any dimension or mixed - i.e.
// array('1' => 2, '2' => array('1' => 3, '2' => 4))
function count_all($arg)
{
// skip if argument is empty
if ($arg) {
// not an array, return 1 (base case)
if(!is_array($arg))
return 1;
// else call recursively for all elements $arg
foreach($arg as $key => $val)
$count += count_all($val);
return $count;
}
}
?>
martin at complinet dot com
30-Nov-2000 12:31
30-Nov-2000 12:31
The count function does not ignore null values in an array. To achieve this use this function.
<?php
function xcount($array) {
while (list($key, $value) = each($array)) {
if ($value) {
$count++;
}
}
return $count;
}
?>
jmcastagnetto at php dot net
04-Sep-2000 07:30
04-Sep-2000 07:30
If you want to disambiguate if a variable contains an array w/ only one element, just us is_array() or gettype()
legobuff at hotmail dot com
02-Feb-2000 06:43
02-Feb-2000 06:43
This is taken from sganer@expio.co.nz comments on the sizeof() function:
If some elements in your array are not set, then sizeof() and count() will not return the index of the last element, but will return the number of set elements. To find the index of the last element in the array:
end($yourArray);
$index = key($yourArray);
... Where $yourArray is the array you want to find the last index ($index) of.