Challenge 2 — Solution

Task: Given an indexed array of 6 numbers of your choice, use
in_array() to check if 42 is present, array_search() to find the index
of a number you know is in there, and sort() to put the array in
ascending order. Echo the result of each step.

<?php
    $numbers = [17, 42, 3, 91, 8, 55];

    var_dump(in_array(42, $numbers));       // is 42 present?
    echo array_search(91, $numbers) . "<br>"; // index of 91

    sort($numbers);
    print_r($numbers);
?>


Output:
bool(true)
3
Array
(
    [0] => 3
    [1] => 8
    [2] => 17
    [3] => 42
    [4] => 55
    [5] => 91
)

Notes:
- in_array(42, $numbers) returns true because 42 genuinely is one of
  the six values in the original array.
- array_search(91, $numbers) returns 3, since 91 sits at index 3 in the
  original, unsorted array ([17, 42, 3, 91, 8, 55]).
- sort() rearranges the array's own values into ascending order and
  re-indexes the keys cleanly from 0 - notice the original insertion
  order is completely gone afterward, replaced by numeric order.