strcspn

(PHP 3 >= 3.0.3, PHP 4, PHP 5)

strcspn --  Find length of initial segment not matching mask

Description

int strcspn ( string str1, string str2 [, int start [, int length]] )

Returns the length of the initial segment of str1 which does not contain any of the characters in str2.

As of PHP 4.3.0, strcspn() accepts two optional integer parameters that can be used to define the start position and the length of the string to examine.

注: 本函数可安全用于二进制对象。

See also strspn().


add a note add a note User Contributed Notes
PHP at NospamImmortalSoFar dot com
08-Oct-2006 09:31
Also useful for breaking down expressions - for example parsing SQL: values ('this', fn("that,)()", 4))

$sep = strcspn ($list, "'\"`");    //    Start of quoted string
$list = substr ($list, $sep);
$find = substr ($list, 0, 1);
while (($sep = strpos ($list, $find, $sep+1)) > 0 && substr ($list, $sep-1, 1) == '\\')
   {}
//  $sep now spans the entire string, regardless of embedded quotes

Once the strings have been removed, an expression can then be parsed for commas and brackets without worrying about them:

while ($out != '')
{
   $sep = strcspn ($list, "(),");      //  Next seperator
...
}
AT-HE (at_he AT hotmai1 DOT com)
27-Dec-2005 06:07
this function can be used like strspn(), except while that can be used to compare a string with an allowed pattern, this one can be use to compare a string with a FORBIDDEN pattern

so, to know if any forbidden character has a position inside our string, we can use (not tested with backslashes)...

<?php
// LARGE VERSION
$forbidden="\"\\?*:/@|<>";
if (
strlen($filename) != strcspn($filename,$forbidden)) {
   echo
"you cant create a file with that name!";
}

// SHORT VERSION
if (strlen($filename) - strcspn($filename,"\"\\?*:/@|<>")) {
   echo
"i told you, you cant create that file";
}
?>
maskedcoder at hotmail dot com
11-Oct-2005 07:13
useful for finding beginning of quotes and/or tags in a variable containing html. 
   $pos = strcspn($data, '<"\'');
will find the first occurance of either the beginning of a tag, or a double- or single-quoted string.