How to loop through, match and replace?

Question

I have multiple strings with same curly braces I want to replace them as dynamic if I get the count as 1 then need to replace the first occurrence, If count as 2 then replaces t

Answer 1

The expression we might wish to design here can be like one of these:

({{)(.+?)(}})

which is only using capturing groups ().

DEMO 1

---

(?:{{)(.+?)(?:}})

and here we can use non-capturing groups (?:), if we do not wish to keep the {{ and }}.

DEMO 2

Then, we could simply do the preg_replace that we wanted to do.

Test

$re = '/(?:{{)(.+?)(?:}})/m';
$str = '{{ONE}} {{TWO}} {{THREE}} {{FOUR}} {{FIVE}} {{SIX}}';
$subst = '$1';

$result = preg_replace($re, $subst, $str);

echo "The result of the substitution is ".$result;