substr_replace

substr_compare

Last updated: Fri, 03 Jul 2009

substr_count

(PHP 4, PHP 5)

substr_count — Count the number of substring occurrences

Description

int substr_count ( string $haystack , string $needle [, int $offset= 0 [, int $length ]] )

substr_count() returns the number of times the needle substring occurs in the haystack string. Please note that needle is case sensitive.

Note: This function doesn't count overlapped substrings. See the example below!

Parameters

haystack: The string to search in
needle: The substring to search for
offset: The offset where to start counting
length: The maximum length after the specified offset to search for the substring. It outputs a warning if the offset plus the length is greater than the haystack length.

Return Values

This functions returns an integer.

Changelog

Version	Description
5.1.0	Added the `offset` and the `length` parameters

Examples

Example #1 A substr_count() example


<?php
$text = 'This is a test';
echo strlen($text); // 14

echo substr_count($text, 'is'); // 2

// the string is reduced to 's is a test', so it prints 1
echo substr_count($text, 'is', 3);

// the text is reduced to 's i', so it prints 0
echo substr_count($text, 'is', 3, 3);

// generates a warning because 5+10 > 14
echo substr_count($text, 'is', 5, 10);


// prints only 1, because it doesn't count overlapped subtrings
$text2 = 'gcdgcdgcd';
echo substr_count($text2, 'gcdgcd');
?>


It was suggested to use



substr_count ( implode( $haystackArray ), $needle );



instead of the function described previously, however this has one flaw.  For example this array:



array (

  0 => "mystringth",

  1 => "atislong"

);



If you are counting "that", the implode version will return 1, but the function previously described will return 0.

zmindster at gmail dot com
23-Mar-2009 10:53


For some who seeked for an easy way to resolve URL composed of /../ like http://w3.host.tld/path/to/the/file/../../file.extension, here is a solution



<?php

$url = 'http://w3.host.tld/path/to/file/../file.extension';



while (substr_count($url, "../"))

{

    $url = preg_replace('#/[^/]+/\.\.#', '', $url);

}

//outputs 'http://w3.host.tld/path/to/file.extension'

?>



and seems to work perfectly!

gigi at phpmycoder dot com
12-Jan-2009 05:17


below was suggested a function for substr_count'ing an array, yet for a simpler procedure, use the following:



<?php

substr_count ( implode( $haystackArray ), $needle );

?>

Anonymous
11-Jul-2008 03:49


It should be noted that unlike the other substr functions, the offset value cannot be a negative value.



<?php

echo substr_count('abcdefg', 'efg', 4, 3); // 1

echo substr_count('abcdefg', 'efg', -3, 3); // warning

?>

danjr33 at gmail dot com
24-Jul-2007 03:37


I ran into trouble using this function when I moved a script from a server with PHP5 to a server with only PHP4.

As the last two parameters were added with 5.1.0, I wrote a substitute function:

<?php

function substr_count5($str,$search,$offset,$len) {

    return substr_count(substr($str,$offset,$len),$search);

}

?>

Use it exactly as substr_count() is used in PHP5. (This will work in PHP5 as well.)

info at fat-fish dot co dot il
06-May-2007 01:07


a simple version for an array needle (multiply sub-strings):

<?php



function substr_count_array( $haystack, $needle ) {

     $count = 0;

     foreach ($needle as $substring) {

          $count += substr_count( $haystack, $substring);

     }

     return $count;

}

?>

flobi at flobi dot com
26-Oct-2006 04:07


Making this case insensitive is easy for anyone who needs this.  Simply convert the haystack and the needle to the same case (upper or lower).



substr_count(strtoupper($haystack), strtoupper($needle))

XinfoX X at X XkarlX X-X XphilippX X dot X XdeX
21-Dec-2003 10:27


Yet another reference to the "cgcgcgcgcgcgc" example posted by "chris at pecoraro dot net":



Your request can be fulfilled with the Perl compatible regular expressions and their lookahead and lookbehind features.



The example



 $number_of_full_pattern = preg_match_all('/(cgc)/', "cgcgcgcgcgcgcg", $chunks);



works like the substr_count function. The variable $number_of_full_pattern has the value 3, because the default behavior of Perl compatible regular expressions is to consume the characters of the string subject that were matched by the (sub)pattern. That is, the pointer will be moved to the end of the matched substring.

But we can use the lookahead feature that disables the moving of the pointer:



 $number_of_full_pattern = preg_match_all('/(cg(?=c))/', "cgcgcgcgcgcgcg", $chunks);



In this case the variable $number_of_full_pattern has the value 6.

Firstly a string "cg" will be matched and the pointer will be moved to the end of this string. Then the regular expression looks ahead whether a 'c' can be matched. Despite of the occurence of the character 'c' the pointer is not moved.

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