Modify a FixedSizeListArray in place

[daniellga]

Hi! While I can very easily modify in place a PrimitiveArray with get_mut_values, I am struggling to modify in place a FixedSizeListArray. I did the code below trying to get a mutable reference to the inner Array or even to get a MutableFixedSizeListArray to no avail. What am I missing here?

Works

        let mut primitive_array =
            PrimitiveArray::from_vec(vec![1., 2., 3., 4., 5., 6., 7., 8., 9., 10., 11., 12.]);
        let b = primitive_array.get_mut_values().unwrap();
        b[0] = 10.;

Doesn't work. Returns None on the last line.

        let array: PrimitiveArray<f32> =
            PrimitiveArray::from_vec(vec![1., 2., 3., 4., 5., 6., 7., 8., 9., 10., 11., 12.]);
        let field = Box::new(Field::new("item", array.data_type().clone(), true));
        let mut fixedlist =
            FixedSizeListArray::try_new(DataType::FixedSizeList(field, 3), Box::new(array), None)
                .unwrap();
        let a = fixedlist
            .as_any_mut()
            .downcast_mut::<MutableFixedSizeListArray<MutablePrimitiveArray<f32>>>()
            .unwrap(); 

Doesn't work. Compiler complain because no conversion is implemented on last line.

        let array: PrimitiveArray<f32> =
            PrimitiveArray::from_vec(vec![1., 2., 3., 4., 5., 6., 7., 8., 9., 10., 11., 12.]);
        let field = Box::new(Field::new("item", array.data_type().clone(), true));
        let mut fixedlist =
            FixedSizeListArray::try_new(DataType::FixedSizeList(field, 3), Box::new(array), None)
                .unwrap();
        let a: MutableFixedSizeListArray<MutablePrimitiveArray<f32>> = fixedlist.into();