PHP Regular Expression:-
Regular expression charecters का sequence या pattern नहीं होता है बल्कि यह हमे pre matching functionality provide करता है । हम regular expression का use करके
particular string किसी दूसरी string को search कर सकते है, refresh कर सकते हैँ, या उन्हें तोड़ (split) कर सकते है । PHP 2 type के regular expression provide करती है जो निम्न है
- Posix regular expression
- PERL style regular expression
Posix regular expression:-posix regular expression वो होते है जो string, charecters, expression
तथा arithmetic expression में pettern matching के लिये use आता है
For Example:- ereg_replace() function का use specify string को किसी special pattern द्वारा search कर उसको किसी दूसरी string से replace करना है इसका syntax निम्न है
Syntax :- string ereg_replace (string pattern, string replacement, string originalstring);
Figure:-1 Use Of ereg_replace() function
उपरोक्त code को जब हम browser पर run कराते है तो following Output produce होता है -
Output
Figure:-2 ereg_replace() function Output
currently posix style regular expression हमें 7 function provide करता है जो कि निम्न है
| Function |
Description |
| ereg() |
The ereg() function searches a string specified by string for a string specified by pattern, returning true if
the pattern is found, and false otherwise. |
| ereg_replace() |
The ereg_replace() function searches for string specified by pattern and replaces pattern with replacement if found. |
| eregi() |
The eregi() function searches throughout a string specified by pattern for a string specified by string. The search is not case sensitive. |
| eregi_replace() |
The eregi_replace() function operates exactly like ereg_replace(), except that the search for pattern in string is not case sensitive. |
| split() |
The split() function will divide a string into various elements, the boundaries of each element based on the occurrence of pattern in string. |
| spliti() |
The spliti() function operates exactly in the same manner as its sibling split(), except that it is not case sensitive. |
| sql_regcase() |
The sql_regcase() function can be thought of as a utility
function, converting each character in the input parameter string into a bracketed expression containing two characters. |
PERL style regular expression:- PHP offers following functions for searching strings using Perl-compatible regular expressions −
| Function |
Description |
| preg_match() |
The preg_match() function searches string for pattern, returning true if pattern exists, and false otherwise. |
| preg_match_all() |
The preg_match_all() function matches all occurrences of pattern in string. |
| preg_replace() |
The preg_replace() function operates just like ereg_replace(), except that regular expressions can be used in the pattern and replacement input parameters. |
| preg_split() |
The preg_split() function operates exactly like split(), except that regular expressions are accepted as input parameters for pattern. |
| preg_grep() |
The preg_grep() function searches all elements of input_array, returning all elements matching the regexp pattern. |
| preg_ quote() |
Quote regular expression characters |