Explicit Key Specification in PHP

If necessary, keys can be specified explicitly:

php<?php
  $arr = []; // create an empty array
  
  $arr[0] = 'a'; // add element 'a' to key 0
  $arr[1] = 'b'; // add element 'b' to key 1
  $arr[2] = 'c'; // add element 'c' to key 2
  
  var_dump($arr); // will output ['a', 'b', 'c']
?>

Keys can be not only numeric, but also string:

php<?php
  $arr = [];
  
  $arr['a'] = 1;
  $arr['b'] = 2;
  $arr['c'] = 3;
  
  var_dump($arr); // will output ['a' => 1, 'b' => 2, 'c' => 3]
?>

php<?php
  $arr = [];
?>