str_replace

sepultura

Hello I'm having a bit of trouble with replace words.
How do I go about replacing whole words only.

For example I want to replace the word head, but I don't want the word headphones to be disturbed.

Is this possible?

devinemke

$string = 'please put the headphones on your head now';
$array = explode(' ', $string);
foreach ($array as $key => $value)
{
	if ($value == 'head') {$array[$key] = 'dog';}
}
echo implode(' ', $array);

madwormer2

What if the word is at the end of the sentence? Or next to a quotation mark?

Megahertza

The above code above seperates all words in the string assuming they have space beside them, then it loops cycle through the words selecting "head" and replacing it with "dog". Since headphones has no spaces between it, its is not seperated nor replaced.

This code will replace the word head at any point in the sentence as long as the word "head" is seperated from other words by a " " ... space

madwormer2

I put the headphones on my head.

If you look at that string, when you explode it, you get:

Array ( [0] => I [1] => put [2] => the [3] => headphones [4] => on [5] => my [6] => head. )

Then when you compare them, "head." will NOT match "head", so will not be replaced.

madwormer2

You could use this:

<?php
$string = 'I put the headphones on my head.';
echo preg_replace('/(\bhead\b)/i','dog',$string);
?>

It matches the word only if it is on it's own (the \b word boundary.)

This outputs: I put the headphones on my dog.

Not that you'd want to do such a thing.