How to Convert Camel Case to Snake Case in PHP ?

How to Convert Camel Case String to Snake Case in JavaScript ?

Given a Camel Case String, the task is to convert the Camel Case String to a Snake Case String in PHP.

Examples:

Input: w3wiki
Output: Beginner_for_Beginner

Input: WelcomeToGfg 
Output: welcome_to_gfg

Camel case uses capital letters at the beginning of each word except the first one, while snake case separates words with underscores and uses all lowercase letters.

Table of Content

Using Manual Conversion
Using Regular Expressions

Approach 1: Using Manual Conversion

The simplest way to convert camel case to snake case is to do it manually by iterating through each character of the string and inserting an underscore before each capital letter.

PHP

<?php 
  
function camelToSnake($camelCase) { 
    $result = ''; 
  
    for ($i = 0; $i < strlen($camelCase); $i++) { 
        $char = $camelCase[$i]; 
  
        if (ctype_upper($char)) { 
            $result .= '_' . strtolower($char); 
        } else { 
            $result .= $char; 
        } 
    } 
  
    return ltrim($result, '_'); 
} 
  
// Driver code 
$camelCase = 'WelcomeTow3wiki'; 
$snakeCase = camelToSnake($camelCase); 
echo $snakeCase; 
  
?>

Output

welcome_to_Beginner_for_Beginner

Approach 2: Using Regular Expressions

Regular expressions provide a concise way to achieve the conversion from camel case to snake case.

PHP

<?php 
  
function camelToSnake($camelCase) { 
    $pattern = '/(?<=\\w)(?=[A-Z])|(?<=[a-z])(?=[0-9])/'; 
    $snakeCase = preg_replace($pattern, '_', $camelCase); 
    return strtolower($snakeCase); 
} 
  
// Driver code 
$camelCase = 'WelcomeTow3wiki'; 
$snakeCase = camelToSnake($camelCase); 
  
echo $snakeCase; 
  
?>