PROGRAMMING
Php
Search
Value Exists
Check if a value exists in an array
$array = array('a'=>1, 'b'=>2, 'c'=>3);
echo in_array(1, $array); // Output: 1
$arr = array ('a' => NULL, 'b' => 2);
echo isset ($arr['a']); // False
echo array_key_exists('a', $arr); // True
Array Search
Array search may return false, always use indentical operator.
$array = array(1,2,3,4);
echo array_search(4, $array); // Output 3
// wrong operator (==)
$array = array(1,2,3,4);
if (array_search(5, $array) == 0) { // true - Look Here
echo 'Found'; // Output: Found!
}
// correct operator (===)
$array = array(1,2,3,4);
if (array_search(5, $array) === 0) { // false - Correct
echo 'Found'; // Output nothing
}
Keys
If the optional search_value is specified, only the keys for that value are returned.
$arr = array('a', 'b', 'a', 'c', 'a', '0', false);
print_r(array_keys($arr)); // [ 0, 1, 2, 3, 4, 5, 6 ]
// Search_value provided
$arr = array('a', 'b', 'a', 'c', 'a', '0', false);
print_r(array_keys($arr, 'a')); // [ 0, 2, 4 ]
// Strict search (identical comparation)
$arr = array('a', 'b', 'a', 'c', 'a', '0', false);
print_r(array_keys($arr, '0')); // [ 5, 6 ] <span class='exclamation'><b>!</b></span> not true
print_r(array_keys($arr, '0', true)); // [ 5 ] corect
➥ Questions
