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    strcspn

    (PHP 4, PHP 5)

    strcspn — Find length of initial segment not matching mask

    Beskrivelse

    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.

    Parametre

    str1

    The first string.

    str2

    The second string.

    start

    The start position of the string to examine.

    length

    The length of the string to examine.

    Returnerings Værdier

    Returns the length of the segment as an integer.

    ChangeLog

    Version Beskrivelser
    4.3.0 The start and length were added

    Eksempler

    Eksempel #1 strcspn() example

    <?php
    $a     = strcspn('abcd',  'apple');
    $b = strcspn('abcd',  'banana');
    $c = strcspn('hello', 'l');
    $d = strcspn('hello', 'world');

    var_dump($a);
    var_dump($b);
    var_dump($c);
    var_dump($d);
    ?>

    The above example will output:

    int(0)
int(0)
int(2)
int(2)

    Noter

    Note: This function is binary-safe.

    Se også

    • strspn() - Finds the length of the initial segment of a string consisting entirely of characters contained within a given mask.

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    User Contributed Notes 5 notes

    up
    7
    maskedcoder at hotmail dot com
    18 years ago
    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.
    up
    6
    AT-HE (at_he AT hotmai1 DOT com)
    18 years ago
    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";
    }
    ?>
    up
    2
    legacyprog at routinz dot net
    13 years ago
    When you use the third parameter remember that the function will return the number of characters it bypassed, which will *not* be the position in your source string.  It's a simple fix to just add your third parameter value to the function result to get the position in the first string where the scan stopped, but I didn't think of it at first.
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    0
    nospam at nospam dot com
    7 years ago
    It might not be clear from the example, that

    strcspn('abcdhelloabcd', 'abcd', -9, -5) == 4

    because it's only evaluating 'hell' which doesn't contain any mask, so returns strlen('hell').
    up
    0
    Anonymous
    14 years ago
    strcspn() can also be thought of as analogous to the following regular expression:
    <?php
    // where ... represents the mask of characters
    preg_match('/[^ ...]/', substr($subject, $start, $length) );
    ?>
    By this analogy, strcspn() can be used in place of some regular expressions to match a pattern without the overhead of a regex engine -- for example, ways to verify if an input string represents a binary value:
    <?php
    preg_match    ('/^[01]+$/i', $subject);
    // or...
    !preg_match('/[^01]/i', $subject);

    // ...or using strcspn()
    !strcspn($subject, '01');
    ?>
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