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# Scope

**Reading** `.npy` and `.npz` files in R.

Writing is out of scope. When working across multiple languages, one should prefer high-performance interoperable format (parquet, zarr, etc.).

# FAQ

## Why not use `reticulate`?

- When reading `.npy` files with `{reticulate}`, at some point in time, two or three copies of the data are made in memory. This can be problematic for large files. With `{grumpy}`, two copies of the data are made in memory, with plans to make just one copy in the cases where the data type matches R native types.

- Reading data with `{reticulate}` requires a Python installation and additional python packages, which users in restricted environments may not have access to. `{grumpy}` is a pure R package with no external dependencies. This is especially important as we expect `{grumpy}` to be used deep in the dependency graph of other packages, and we want to minimize the number of dependencies.
- A dedicated R package gives us more flexibility in how edge cases such as 64 bits integers are handled. `{reticulate}` automatically and silently converts 64 bits integers to double, which is a sensible default for many use cases. But we may want to have more control over this behavior, and `{grumpy}` will allow us to do that in the future. Another good example are structured data types (record arrays), which are returned as data.frames, not arrays, with `{reticulate}`.