PHP数组搜索 - key => string

$array = array(
    "key1" => "value1",
    "key2" => "value2",
    "key3" => "value3"
);

$key = "key";
$result = array_search($key, $array);

if ($result) {
    echo "Key found in array: " . $result;
} else {
    echo "Key not found in array.";
}

Key found in array: key1

$key = "key";
$result = array_search($key, $array, true);