二維數組根據某個相同的值歸類

$arr = [ 0 => [ "category" => "red", "price" => 95 ], 1 => [ "category" => "blue", "price" => 85 ], 2 => [ "category" => "red", "price" => 75 ] ]; //我但願將以上其歸類爲以下數組 [ "red" => [ 0 => [ "category" => "r

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