strcspn
(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.
Parameters
-
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.
Return Values
Returns the length of the segment as an integer.
Changelog
| Version | Description |
|---|---|
| 4.3.0 |
The start and length
were added
|
Examples
Example #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($d);
?>
The above example will output:
int(0) int(0) int(2) int(2)
Notes
Note: This function is binary-safe.
See Also
- strspn() - Finds the length of the initial segment of a string consisting entirely of characters contained within a given mask.
- addcslashes
- addslashes
- bin2hex
- chop
- chr
- chunk_split
- convert_cyr_string
- convert_uudecode
- convert_uuencode
- count_chars
- crc32
- crypt
- echo
- explode
- fprintf
- get_html_translation_table
- hebrev
- hebrevc
- hex2bin
- html_entity_decode
- htmlentities
- htmlspecialchars_decode
- htmlspecialchars
- implode
- join
- lcfirst
- levenshtein
- localeconv
- ltrim
- md5_file
- md5
- metaphone
- money_format
- nl_langinfo
- nl2br
- number_format
- ord
- parse_str
- printf
- quoted_printable_decode
- quoted_printable_encode
- quotemeta
- rtrim
- setlocale
- sha1_file
- sha1
- similar_text
- soundex
- sprintf
- sscanf
- str_getcsv
- str_ireplace
- str_pad
- str_repeat
- str_replace
- str_rot13
- str_shuffle
- str_split
- str_word_count
- strcasecmp
- strchr
- strcmp
- strcoll
- strcspn
- strip_tags
- stripcslashes
- stripos
- stripslashes
- stristr
- strlen
- strnatcasecmp
- strnatcmp
- strncasecmp
- strncmp
- strpbrk
- strpos
- strrchr
- strrev
- strripos
- strrpos
- strspn
- strstr
- strtok
- strtolower
- strtoupper
- strtr
- substr_compare
- substr_count
- substr_replace
- substr
- trim
- ucfirst
- ucwords
- vfprintf
- vprintf
- vsprintf
- wordwrap
Коментарии
useful for finding beginning of quotes and/or tags in a variable containing html.$pos = strcspn($data, '<"\'');
will find the first occurance of either the beginning of a tag, or a double- or single-quoted string.
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";
}
?>
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');
?>
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.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').