PHP recursion and loop to achieve string flipping

This article mainly introduces the method of realizing the string reversal function in PHP, and combines the examples to compare and analyze the relevant operating techniques of PHP using recursive and loop algorithms to realize the string reversal function. Friends who need it can refer to it

The example in this article describes how to implement the string flip function in PHP. Share it with everyone for your reference, the details are as follows:

When it comes to the method of achieving string reversal, everyone will think of using a loop. Indeed, looping is a small memory footprint and simple to implement. But there is another way to achieve such a function, and that is recursion.

php supports recursive functions, which are functions that call themselves. These functions are particularly useful for dynamically browsing data structures such as joined lists and trees.

Example:

<?php 
//递归实现字符串翻转
function reverse_r($str){
  if(strlen($str)>0){
    reverse_r(substr($str,1));
  }
  echo substr($str,0,1);
  return;
}
//循环实现字符串翻转
function reverse_i($str){
  for($i=1; $i<=strlen($str);$i++){
    echo substr($str,-$i,1);
  }
  return;
}
reverse_r("Hello");
reverse_i("everyone");
?>

Result:

Related recommendations:

Methods to implement string flipping in php

2 ways to implement string flipping in js are shared

How to implement string flip function in PHP

The above is the detailed content of PHP recursion and loop to achieve string flipping. For more information, please follow other related articles on the PHP Chinese website!