Thoughts on `Enum.compact/1`

[Patrick Van Stee]

Would implementing an `Enum.compact/1` be useful to anyone? It would basically just be the same as calling `Enum.reject` with `&nil?/1`.

Here's an example:

iex> Enum.compact([1, nil, 3, nil, 5])  

[1, 3, 5]

[Gustavo Brunoro]

In my opinion it's just noise, at it's a really trivial function.

Speaking of that, what's the point of having both Enum.reject and Enum.filter?

2013/8/26 Patrick Van Stee <van...@bignerdranch.com>

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[Peter Minten]

Probably that reject is quite common and the rather simple function for
it helps clearly express the function of the code while filter with an
inverted test requires more thinking.

I agree that it's a bit trivial.

[Steve Downey]

This is probably my Ruby experience/bias exposing itself but:

- removing nil elements from a collection is a common pattern

- Enum.compact(list) is more intention-revealing than Enum.reject(list, &(nil?(&1)))

[Sam Davies]

+1 for this

[OvermindDL1]

If you use an erlang nil `[]` (the empty list) instead of a Elixir's `nil` (which is an atom, which is weird) as nil's then you can just use `:lists.flatten`.

[Paul Schoenfelder]

This is probably my Ruby experience/bias exposing itself but:

- removing nil elements from a collection is a common pattern

- Enum.compact(list) is more intention-revealing than Enum.reject(list, &(nil?(&1)))

I really don't agree that `Enum.compact(list)` is somehow more revealing than `Enum.reject(list, &is_nil/1)` - it is clear what the latter will do, it is not clear what the former will do. I think there is a lot more of the Ruby bias in this statement than you think ;). I'm not sold on the idea of adding a function to the standard library which is so trivially written with functions that already exist, at the sacrifice of clarity.

Paul

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[binaryseed]

It's even clearer written like this:

Enum.reject(list, &is_nil/1)

On Wednesday, May 17, 2017 at 8:29:15 AM UTC-7, Paul Schoenfelder wrote:

This is probably my Ruby experience/bias exposing itself but:

- removing nil elements from a collection is a common pattern

- Enum.compact(list) is more intention-revealing than Enum.reject(list, &(nil?(&1)))

I really don't agree that `Enum.compact(list)` is somehow more revealing than `Enum.reject(list, &is_nil/1)` - it is clear what the latter will do, it is not clear what the former will do. I think there is a lot more of the Ruby bias in this statement than you think ;). I'm not sold on the idea of adding a function to the standard library which is so trivially written with functions that already exist, at the sacrifice of clarity.

Paul

On Wed, May 17, 2017 at 10:14 AM, OvermindDL1 <overm...@gmail.com> wrote:

If you use an erlang nil `[]` (the empty list) instead of a Elixir's `nil` (which is an atom, which is weird) as nil's then you can just use `:lists.flatten`.

On Wednesday, May 17, 2017 at 4:28:30 AM UTC-6, Sam Davies wrote:

+1 for this

On Wednesday, August 28, 2013 at 5:49:33 PM UTC+1, Steve Downey wrote:

This is probably my Ruby experience/bias exposing itself but:

- removing nil elements from a collection is a common pattern

- Enum.compact(list) is more intention-revealing than Enum.reject(list, &(nil?(&1)))

On Monday, August 26, 2013 3:40:33 PM UTC-7, Patrick Van Stee wrote:

Would implementing an `Enum.compact/1` be useful to anyone? It would basically just be the same as calling `Enum.reject` with `&nil?/1`.

Here's an example:

iex> Enum.compact([1, nil, 3, nil, 5])  

[1, 3, 5]

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