compact
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 :)
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;
}
count
(PHP 4, PHP 5)
count — Count elements in an array, or properties in an object
Description
Counts elements in an array, or properties in an object.
For objects, if you have SPL installed, you can hook into count() by implementing interface Countable. The interface has exactly one method, count(), which returns the return value for the count() function.
Please see the Array section of the manual for a detailed explanation of how arrays are implemented and used in PHP.
Parameters
- var
-
The array.
- mode
-
If the optional mode parameter is set to COUNT_RECURSIVE (or 1), count() will recursively count the array. This is particularly useful for counting all the elements of a multidimensional array. The default value for mode is 0. count() does not detect infinite recursion.
Return Values
Returns the number of elements in var , which is typically an array, since anything else will have one element.
If var is not an array or an object with implemented Countable interface, 1 will be returned. There is one exception, if var is NULL, 0 will be returned.
Caution
count() may return 0 for a variable that isn't set, but it may also return 0 for a variable that has been initialized with an empty array. Use isset() to test if a variable is set.
ChangeLog
| Version | Description |
|---|---|
| 4.2.0 | The optional mode parameter was added. |
Examples
Example #1 count() example
<?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 Recursive count() example
<?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($food); // output 2
?>
add a note
User Contributed Notescount
michael.debyl at gmail dot comz0r
16-Jul-2008 03:45
16-Jul-2008 03:45
analpaper{gmail}
03-Jul-2008 07:37
03-Jul-2008 07:37
I found useful this little function that detects if a array is multidimensional or not.
<?php
function array_is2D($array) {
return is_array($array) ? count($array)===count($array, COUNT_RECURSIVE) : -1;
}
?>
---
live2code
macnimble
20-Apr-2008 04:57
20-Apr-2008 04:57
In response to yarolan at mail dot ru:
I actually find Duff's Device to be particularly useful in the example put forth by yarolan.
He wrote:
$arr_size=count($arr);
for($i=0;$i<$arr_size;$i++)
{
...
}
If the order of processing doesn't matter, I do this:
$i = count($some_array);
while ($i--):
do_something_to($some_array[$i]);
endwhile;
If it does matter, I like this:
$i = count($some_array);
$some_array = array_reverse($some_array);
while ($i--):
do_something_to($some_array[$i]);
endwhile;
I have no idea if it's faster as I haven't tested it.
Mostly, I just like the way it looks. ;)
To email me, find me on TheHolierGrail.com or MacNimble.com
Anonymous
11-Jan-2008 01:20
11-Jan-2008 01:20
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 $cnt;
}
?>
Anonymous
16-Nov-2007 08:31
16-Nov-2007 08:31
I can confirm Wulfson's comment below. The for loop should be
faster in most situations, just as long as you're iterating through a
sequentially indexed array.
In fact, from my experience using foreach to iterate through an associative array is actually slower than using a while loop.
<?php
/* foreach iterator */
foreach($assoc_array as $key => $value) { }
/* while iterator */
while(list($key, $value) = each($assoc_array)) { }
?>
Wulfson at wulfden dot com
02-Nov-2007 02:08
02-Nov-2007 02:08
The last two comments (redbehelit and Jaik) are a little misguided. In a 26 element array,
for ($i = 0; $i < count($arr); $i++) {
works just fine, as count($arr) will return 26, which means that the
loop will end as soon as $i gets iterated to 26 (26 < 26 is false).
You'd only have to use count($arr) - 1 if your conditional was $i <=
Jaik is correct that it's better not to use count() inside the loop
construct. As mentioned in a previous comment, it'd be faster to use
$size = count($arr);
for ($i = 0; $i < $size; $i++) {
I don't agree that foreach should be used instead of this, however. In
my trials, I found that using a normal for loop was consistently faster
than using a foreach (granted, not a whole lot faster, but everything
counts if you're trying to optimize). foreach really ought to only be
used when the array you're traversing contains associative indices.
Jaik
25-Oct-2007 06:51
25-Oct-2007 06:51
The last comment is somewhat inefficient as it runs the count() function at the start of every loop.
The preferred way to iterate through an array would be to use the 'foreach' control structure.
redbehelit at yahoo dot com
16-Oct-2007 12:24
16-Oct-2007 12:24
Be careful if you're using count in a loop. Example:
$arr ends at index number 25 (or $arr[25])
We know there are actually 26 elements when we include element 0 (as we
should). This is what count is going to return back. But if we do this:
for ($i = 0; $i < count($arr); i++) {
This loop is going to try to traverse to $arr[26] which does not exist.
The last element is at index number 25. We can fix this with a minor
edit:
for ($i = 0; $i < count($arr)-1; i++) {
atoi_monte at hotmail dot com
28-Jun-2007 02:10
28-Jun-2007 02:10
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 01:14
13-Jun-2007 01:14
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 04:56
26-Apr-2007 04:56
NEVER USE IN CYCLES!
//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 07:24
03-Feb-2007 07:24
// 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 $count;
}
alexandr at vladykin dot pp dot ru
08-Nov-2006 04:28
08-Nov-2006 04:28
My function returns the number of elements in array for
multidimensional arrays subject to depth of array. (Almost
COUNT_RECURSIVE, but you can point on which depth you want to plunge).
<?
function getArrCount ($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 12:32
26-Jan-2006 12:32
<?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 05:59
20-Dec-2005 05:59
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
30-Nov-2005 04:57
30-Nov-2005 04:57
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 09:16
18-Oct-2005 09:16
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
------------------------------
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
12-Feb-2005 04:30
12-Feb-2005 04:30
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
19-Nov-2004 05:01
19-Nov-2004 05:01
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($food,0)); //output 6
?>
moazzam at ummah dot org
14-Oct-2004 04:59
14-Oct-2004 04:59
This is an obvious note, but I am writing it any way so other, who did may not have observed this, can take advantage of it too.
When running loops with count conditions, the code runs faster if you
first assign the count() value to a variable and use that (instead of
using count() directly in a loop condition.
To explain my point better, here is an example:
<?php
for ($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 10:30
04-Jun-2004 10:30
I have found on upload scripts or on file manipulation scripts that people can trick a classic file type filter:
example:
$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:
$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
30-Mar-2004 04:13
30-Mar-2004 04:13
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($a)); //prints 0
?>
admin at lft-muenchen dot de
12-Mar-2003 04:18
12-Mar-2003 04:18
Note:
print (strlen($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 12:40
20-Aug-2002 12:40
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
08-Jul-2002 09:18
Perhaps change the wording of this description from "Count elements in
a variable" to "Count total elements in a variable" as it may be
interpreted (by me) as a function for counting specific elements (ie,
number of substrings)
webmaster at NOSPAMtrafficg dot com
26-Apr-2002 03:48
26-Apr-2002 03:48
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
?>
07-Feb-2002 06:01
<?php
count(false) ==1
?>
this has tripped me up before...
kanareykin at denison dot edu
26-Mar-2001 01:13
26-Mar-2001 01:13
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 $count;
}
}
?>
martin at complinet dot com
30-Nov-2000 04:31
30-Nov-2000 04:31
The count function does not ignore null values in an array. To achieve this use this function.
<?php
function xcount($array) {
while (list($key, $value) = each($array)) {
if ($value) {
$count++;
}
}
return $count;
}
?>
jmcastagnetto at php dot net
04-Sep-2000 12:30
04-Sep-2000 12:30
If you want to disambiguate if a variable contains an array w/ only one element, just us is_array() or gettype()
legobuff at hotmail dot com
02-Feb-2000 10:43
02-Feb-2000 10:43
This is taken from sganer@expio.co.nz comments on the sizeof() function:
If some elements in your array are not set, then sizeof() and count()
will not return the index of the last element, but will return the
number of set elements. To find the index of the last element in the
array:
end($yourArray);
$index = key($yourArray);
... Where $yourArray is the array you want to find the last index ($index) of.