How to use Associative Array In PHP

Using array_count_values() Function

One of the most basic methods is to use an associative array to keep track of the occurrence of each character in the string.

PHP

<?php 
  
function printDuplicates($str) { 
    $charCount = []; 
  
    // Iterate through each character 
    // in the string 
    for ($i = 0; $i < strlen($str); $i++) { 
        $char = $str[$i]; 
  
        // Check if the character is already 
        // in the associative array 
        if (isset($charCount[$char])) { 
            $charCount[$char]++; 
        } else { 
            $charCount[$char] = 1; 
        } 
    } 
  
    // Print duplicate characters 
    echo "Duplicate characters: "; 
    foreach ($charCount as $char => $count) { 
        if ($count > 1) { 
            echo "$char "; 
        } 
    } 
} 
  
// Driver code 
$str = "Welcome to w3wiki"; 
printDuplicates($str); 
  
?>

Output

Duplicate characters: e o   G k s

PHP Program to Print All Duplicate Characters in a String

This article will show you how to print duplicate characters in a string using PHP. Detecting and printing duplicate characters in a string is a common task in programming. In this article, we will explore various approaches to achieve this.

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