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ereg_replace

(PHP 3, PHP 4 , PHP 5)

ereg_replace -- Replace regular expression

Description

string ereg_replace ( string pattern, string replacement, string string )

This function scans string for matches to pattern, then replaces the matched text with replacement.

The modified string is returned. (Which may mean that the original string is returned if there are no matches to be replaced.)

If pattern contains parenthesized substrings, replacement may contain substrings of the form \\digit, which will be replaced by the text matching the digit'th parenthesized substring; \\0 will produce the entire contents of string. Up to nine substrings may be used. Parentheses may be nested, in which case they are counted by the opening parenthesis.

If no matches are found in string, then string will be returned unchanged.

For example, the following code snippet prints "This was a test" three times:

Пример 1. ereg_replace() example


<?php



$string 
= 
"This is a test"
;

echo 
str_replace
(
" is"
, 
" was"
, 
$string
);

echo 
ereg_replace
(
"( )is"
, 
"\\1was"
, 
$string
);

echo 
ereg_replace
(
"(( )is)"
, 
"\\2was"
, 
$string
);




?>

One thing to take note of is that if you use an integer value as the replacement parameter, you may not get the results you expect. This is because ereg_replace() will interpret the number as the ordinal value of a character, and apply that. For instance:

Пример 2. ereg_replace() example


<?php


/* This will not work as expected. */


$num 
= 
4
;


$string 
= 
"This string has four words."
;


$string 
= 
ereg_replace
(
'four'
, 
$num
, 
$string
);

echo 
$string
;   
/* Output: 'This string has   words.' */



/* This will work. */


$num 
= 
'4'
;


$string 
= 
"This string has four words."
;


$string 
= 
ereg_replace
(
'four'
, 
$num
, 
$string
);

echo 
$string
;   
/* Output: 'This string has 4 words.' */


?>

Пример 3. Replace URLs with links


<?php

$text 
= 
ereg_replace
(
"[[:alpha:]]+://[^<>[:space:]]+[[:alnum:]/]"
,

                     
"<a href=\"\\0\">\\0</a>"
, 
$text
);


?>

Подсказка: preg_replace(), which uses a Perl-compatible regular expression syntax, is often a faster alternative to ereg_replace().

Смотрите также ereg(), eregi(), eregi_replace(), str_replace(), and preg_match().

Все функции PHP: