Creating mutable array from references?

[Arty-Maly]

Hi, I am curious if there is a way to create a MutablePrimitiveArray from a section of values from another MutablePrimitiveArray?

They way I understand it, I will always incur a copy cost? There would be no way to have a zero copy in this situation?
I was hoping to pass a ref of the values from one array to another.

[sundy-li]

MutablePrimitiveArray need to own Vec<T>, so if you want to create it from another MutablePrimitiveArray, you need to move the memory otherwise it will have copy cost.

[Arty-Maly]

Ok. Thanks for your quick response.

One workaround I thought of was to convert MutablePrimitiveArray to PrimitiveArray (which is O(1)) and then use PrimitiveArrays with the slice method. That would give me a zero copy as I understand it, correct?

One downside is that I lose the mutability while I have the extra slices in use. (Can’t conver back to mutable array)

[jorgecarleitao]

Yes, you can think of them as struct MutablePrimitiveArray(Vec<T>) and struct PrimitiveArray(Arc<Vec<T>>, offset, length) where offset and length correspond to the slice. This is why PrimitiveArray has a O(1) cost of slicing.

[Arty-Maly]

Thanks for helping me understand.