How do I remove the space in the output of this regex?

Question

I’m using regex in PHP. This is my script:

$s="2044 blablabla  2033 blablabla 2088";
echo preg_replace("/(20)\d\d/","$1 14",$s);

The result was like this:

20 14 blablabla 20 14 blablabla 20 14

I want to remove the space between the 20 and the 14 to get the result 2014. How do I do that?

RTM: http://php.net/manual/en/function.preg-replace.php – Salman A Sep 12 '14 at 17:21 — Salman A, Sep 12 '14 at 17:21

score 12 · Answer 1 · answered Sep 12 '14 at 13:18

12

You need to use curly brackets inside single quotes:

echo preg_replace("/(20)\d\d/",'${1}14',$s);

answered Sep 12 '14 at 13:18

Casimir et Hippolyte

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hjpotter92 · Answer 2 · 2014-09-12T13:36:29.373

7

After checking the preg_replace manual:

When working with a replacement pattern where a backreference is immediately followed by another number (i.e.: placing a literal number immediately after a matched pattern), you cannot use the familiar \\1 notation for your backreference. \\11, for example, would confuse preg_replace() since it does not know whether you want the \\1 backreference followed by a literal 1, or the \\11 backreference followed by nothing. In this case the solution is to use \${1}1. This creates an isolated $1 backreference, leaving the 1 as a literal.

Therefore, use

"\${1}14"

or

'${1}14'

edited Sep 12 '14 at 13:36

answered Sep 12 '14 at 13:12

hjpotter92

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new result like this 4 blablabla 4 blablabla 4 – ro0xandr Sep 12 '14 at 13:14
@ro0xandr Check the edit above. – hjpotter92 Sep 12 '14 at 13:19
@CasimiretHippolyte beat you by 8 secs...!! :D – NoobEditor Sep 12 '14 at 13:20

score 4 · Accepted Answer · answered Sep 12 '14 at 13:17

4

You could simply do like this,

$s="2044 blablabla  2033 blablabla 2088";
echo preg_replace("/(20\d\d)/","2014",$s);

answered Sep 12 '14 at 13:17

Avinash Raj

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mmmm....you are hardcoding `$1` with `20`!??? – NoobEditor Sep 12 '14 at 13:18
1

he used this pattern `(20)\d\d` not `(\d\d)\d\d` – Avinash Raj Sep 12 '14 at 13:19
yes it works for this problem, it not general solution , thank for all – ro0xandr Sep 12 '14 at 13:25

score 2 · Answer 4 · answered Sep 12 '14 at 13:17

2

You need to use preg_replace_callback() function:

echo preg_replace_callback("/(20)\d\d/", function($number) {
    return $number[1].'14';
},$s);

// 2014 blablabla 2014 blablabla 2014

answered Sep 12 '14 at 13:17

Marcin Nabiałek

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How do I remove the space in the output of this regex?

4 Answers4