The implode() function is a built-in function of PHP, and it works the same as the join() function works. It is used to join the elements of an array and convert them into a string. PHP implode() function accepts two parameters as arguments; one is required, and one is optional. The first parameter is “separator,” which gives a separator between the values in the form of a string. The elements of an array join to form a string, and each value will be separated by a separator given in parameter. This parameter is an optional parameter by default; it takes an empty string. The second parameter is “array,” and it is a required parameter. It is the one whose value is to be changed. This PHP implode() function will return a string that is formed with the elements of an array.
Table of Contents
Syntax
implode(separator,array)
Convert an Array to String: Example
In this example, we will perform array to string conversion using PHP implode() function. We will create an array of fruits and convert it into a string. A comma will separate each item.
Code
<?php
$ar = ['apple', 'orange', 'pear', 'grape'];
echo "Fruits Array";
echo "<br>";
echo implode(', ', $ar);
?>
Output

Convert an Array of Array to a String: Example
We can also convert an array of the array means a nested array, into a string by using the PHP implode() function. The below example will show that how to do it.
Code
<?php
$movies = [
'comedy' => ['In the Loop', '21 Jump Street', 'Elf ', 'This Is the End'],
'war' => ['Dunkirk', 'Hacksaw Ridge', 'Inglourious Basterds', 'Defiance'],
'action' => ['La La Land', 'The Notebook', 'About Time', 'Twilight'],
'sci fi' => ['Interstellar', 'Annihilation', 'Gravity', 'Inception'],
];
foreach ($movies as $list){
echo "<br>";
print_r(implode(", ", $list));
}
?>
Output

Conclusion
In conclusion, we discussed the PHP implode() function converting an array or array of arrays into a string. It was accepting two parameters one was required the “array,” and one was optional the “separator.” Two coding examples are also given. That will make your concept clearer.