php 通过值获取key

$array = [
    'a' => 'apple',
    'b' => 'banana',
    'c' => 'cherry'
];

$value = 'banana';
$key = array_search($value, $array);

if ($key !== false) {
    echo "找到值 '{$value}' 对应的键为 '{$key}'";
} else {
    echo "未找到值 '{$value}'";
}

$array = [
    'a' => 'apple',
    'b' => 'banana',
    'c' => 'banana'
];

$value = 'banana';
$flippedArray = array_flip($array);
$key = array_search($value, $flippedArray);

if ($key !== false) {
    echo "找到值 '{$value}' 对应的键为 '{$key}'";
} else {
    echo "未找到值 '{$value}'";
}

$array = [
    'a' => 'apple',
    'b' => 'banana',
    'c' => 'cherry'
];

$value = 'banana';
$keys = [];

foreach ($array as $key => $val) {
    if ($val === $value) {
        $keys[] = $key;
    }
}

if (!empty($keys)) {
    echo "找到值 '{$value}' 对应的键为 " . implode(', ', $keys);
} else {
    echo "未找到值 '{$value}'";
}