foreach访问索引或关联数组

// 索引数组
$colors = array("red", "green", "blue");

foreach ($colors as $value) {
    echo $value . "\n";
}

// 输出：
// red
// green
// blue

// 关联数组
$fruits = array(
    "apple" => "red",
    "banana" => "yellow",
    "orange" => "orange"
);

foreach ($fruits as $key => $value) {
    echo $key . ": " . $value . "\n";
}

// 输出：
// apple: red
// banana: yellow
// orange: orange