What is implode?

implode is a built-in PHP function that concatenates elements of an array into a string. It takes two parameters: a separator that is placed between each element in the string and the array of elements to be concatenated. The function is useful for converting an array into a single string, such as when constructing SQL queries or outputting data in a specific format.

Here is an example of how implode can be used:

$array = array('apple', 'banana', 'cherry');
$separator = ', ';
$string = implode($separator, $array);

echo $string;
// Output: apple, banana, cherry

It is important to note that implode only works with arrays as input and returns a string as output. If a non-array input is provided, the function will generate a warning and return NULL.