Splat Operator in PHP

Php-mysql Course

The splat operator was introduced in PHP starting with version 5.6, so, to can use it and test the examples from this page, you need PHP 5.6+.
The Splat Operator is represented by three dots (...), and can be used to define functions that can be called with a variable number of arguments.

1. This operator can be used when the function is called, before an array argument.

<?php
function add($a, $b, $c) {
  return $a + $b + $c;
}

$arguments = [8, 9];     // array with values for $b and $c parameters
echo add(5, ...$arguments);      // 22
?>

2. The splat operator can also be used when the function is defined, before a parameter that represents an array of arguments.

<?php
// $params is an array containing the remaining arguments
function add($opt = 0, ...$params) {
  $sum = $opt + array_sum($params);
  echo '$opt is '. $opt .' / $params contains '. count($params .' arguments / $sum = '. $sum;    
}

add();             // $opt is 0 / $params contains 0 arguments / $sum = 0
add(1);            // $opt is 1 / $params contains 0 arguments / $sum = 1
add(5, 6);         // $opt is 5 / $params contains 1 arguments / $sum = 11
add(5, 6, 7);      // $opt is 5 / $params contains 2 arguments / $sum = 18
add(5, 6, 7, 8);   // $opt is 5 / $params contains 3 arguments / $sum = 26
?>