Using regex in php to find string values between characters multiple times

Question

Here I have a string, "Hello World! I am trying out regex in PHP!". What I want to do is retrieve string values between a set of characters. In this example, the characters are ** **

$str = "**Hello World!** I am trying out regex in PHP!";
preg_match('#\*\*(.*)\*\*#Us', $str, $match);
echo $match[1];

This will echo out "Hello World!", but I want to echo out several matches:

$str = "**Hello World!** I am trying out **regex in PHP!**";

How would I be able to do so? I tried using preg_match_all() but I don't think I was using it properly, or that it would work at all in this case.

anubhava · Accepted Answer · 2015-03-21 14:29:08Z

2

You can use:

$str = "**Hello World!** I am trying out **regex in PHP!**";
preg_match_all('/\*{2}([^*]*)\*{2}/', $str, $m);

print_r($m[1]);
Array
(
    [0] => Hello World!
    [1] => regex in PHP!
)

Even your regex #\*\*(.*)\*\*#Us should work with this but my suggested regex is little more efficient due to negation based pattern [^*]*

answered Mar 21, 2015 at 14:29

anubhava

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rahulinaction · Accepted Answer · 2015-03-21 14:58:44Z

2

You got 1 match owing to using preg_match.You should use preg_match_all Here is another pattern.It uses word non word match between the delimiters

<?php
    $str = "**Hello World!** I am trying out **regex in PHP!**";
    $regex='/\*\*([\w\W]*)\*\*/iU';
    preg_match_all($regex, $str, $m); 
    print_r($m[1]);

edited Mar 21, 2015 at 14:58

answered Mar 21, 2015 at 14:40

rahulinaction

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1 Comment

mickmackusa Over a year ago

Which part of your regex is benefiting from that i pattern modifier?

Avinash Raj · Accepted Answer · 2015-03-21 15:14:27Z

1

I suggest you to use a non-greedy form of regex. Because i think you want to match also the contents (text inside **) where the single * resides.

$str = "**Hello World!** I am trying out **regex in PHP!**";
preg_match_all('~\*\*(.*?)\*\*~', $str, $matches);
print_r($matches[1]);

DEMO

edited Mar 21, 2015 at 15:14

answered Mar 21, 2015 at 15:07

Avinash Raj

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