二维数组根据某个相同的值归类

$arr = [ 0 => [ "category" => "red", "price" => 95 ], 1 => [ "category" => "blue", "price" => 85 ], 2 => [ "category" => "red", "price" => 75 ] ]; //我但愿将以上其归类为以下数组 [ "red" => [ 0 => [ "category" => "r

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