How do I replace certain parts of my string?

Question

How can I replace a certain part of my string with another one?

Input string:

\"Hello, my name is Santa\"

How can I change all

Answer 1

Use function preg_replace()

$text ='this is the old word';

echo $text;
echo '
';

$text = preg_replace('/\bold word\b/', 'NEW WORD', $text);

echo $text;