Replace characters when not followed by certain characters

[LLeoun]

Hi all,

 

I need to replace one character when  it does not come along with certain characters.

Let me explain it with an example:

 

I want to replace the letter o by the letter a when o is not followed by an r

So  the sentence: hello world

Should be transformed into:  hella world

 

How can I do that??

 

Thanks once again

[Mark Baker]

$string = 'hello world';

$result = preg_replace('/o(?=[^r])/i','a',$string);

echo $result;

[thebadbad]

You can use a negative lookahead (?!regex), only matching when the regex fails to match:

 

<?php
$str = 'Hello world!';
echo preg_replace('~o(?!r)~i', 'a', $str);
//Hella world!
?>

 

Remove the i if the search shouldn't be case insensitive.

[thebadbad]

$string = 'hello world';

$result = preg_replace('/o(?=[^r])/i','a',$string);

echo $result;

 

That won't replace an o at the last position in the string.

[LLeoun]

Thanks a ton, worked great!