Understanding PHP String Handling and Techniques to Reverse a String

In many technical interviews, demonstrating PHP string‑handling skills is a key way to stand out.

Does PHP treat strings as arrays?

This is a common misconception. Although you can access a character with $string[int] like an array element, PHP does not treat a string as a true array.

So how does this “black magic” work? When you use the offset syntax, PHP internally performs a string‑offset operation that simply fetches the character at the specified position without treating the string as an array.

Getting back on track, how can you reverse a string in PHP? There are many ways; here are several recommended techniques.

Using PHP built‑in string functions

function revString($string) {
  echo strrev($string);
}

Using partial built‑in functions

function revString($string) {
  for($i = strlen($string); $i > 0; $i--) {
    echo $string[$i-1];
  }
}

Without any PHP string functions

function revString($string) {
  $i = 0;
  $s = "";
  while(!empty($string[$i])) {
    $s = $string[$i] . $s;
    $i++;
  }
  echo $s;
}

The above code may look complex; let’s analyze each loop’s output step by step for better understanding.

For example, assuming the string is "aidni", the output after each iteration would be:

i   // iteration 1
in  // iteration 2
ind // iteration 3
indi // iteration 4
india // iteration 5