Sorting concept

[colinleach]

An attempt to address issue #1043.

Placing this in the syllabus will be an interesting challenge. We want it fairly early, to introduce students to mutating and non-mutating functions. On the other hand, the About touches on a wild variety of more advanced concepts, which we'll need to work around.

I'm tentatively thinking the sequence will be either Ranges -> Sorting -> Vector Operations or Vector Operations -> Sorting -> Functions.

Maybe this will be clearer once we have an exercise? I haven't found anything on another track that covers specifically this topic.

[depial]

This all looks good! Just a couple of minor suggestions and a possible switch in an example.

With the exclusion of broadcasting, I think that there is enough in Ranges to have this follow. I'd imagine that we'll end up deleting the bits on multi-dimensional sorting in the introduction.md but everything else seems to be at an appropriate level.

[depial]

If it's not too much information, an example I have found useful is something like:

julia> tups = [(1, 3), (4, 2), (3, 4), (2, 1)];

julia> sort(tups, by=last)
4-element Vector{Tuple{Int64, Int64, Int64}}:
 (2, 1)
 (4, 2)
 (1, 3)
 (3, 4)

This also kinda gives a nice segue to the multi-dimensional arrays part.

Full example

julia> tups = [(1, 3), (4, 2), (3, 4), (2, 1)];

julia> sort(tups)
4-element Vector{Tuple{Int64, Int64, Int64}}:
 (1, 3)
 (2, 1)
 (3, 4)
 (4, 2)

julia> sort(tups, by=last)
4-element Vector{Tuple{Int64, Int64, Int64}}:
 (2, 1)
 (4, 2)
 (1, 3)
 (3, 4)

[colinleach]

I added this to About, with a forward-reference to the Tuples concept. I think it's too advanced for the Introduction.

[depial]

Oops! I'd forgotten about where Tuples come in. We could change this to Vectors and get the same effect:

julia> vecs = [[1, 3], [4, 2], [3, 4], [2, 1]];

julia> sort(vecs)  # by default sorts by the first element of the vectors
4-element Vector{Vector{Int64}}:
 [1, 3]
 [2, 1]
 [3, 4]
 [4, 2]

julia> sort(vecs, by=last)
4-element Vector{Vector{Int64}}:
 [2, 1]
 [4, 2]
 [1, 3]
 [3, 4]

[depial]

Also, there might be a stray "about" in the last line:

The final example about will be explained in more detail in the [Tuples Concept][concept-tuples].

[colinleach]

Honestly, I'm fine with tuples for now. Let's wait and see what the exercise ends up needing: this bit may end up being removed from the Introduction regardless.

[colinleach]

we'll end up deleting the bits on multi-dimensional sorting in the introduction.md

I'd already done that. I just checked, and I'd really done that (apart from a stray URL in the references), not just imagined it!

[depial]

I'd already done that.

Sorry about that! I was operating under the (unjustified) assumption that introduction.md was still just a copy of about.md, so I didn't even go through it...

[colinleach]

The Introduction appears on the website under my own account, and the About in incognito - nice! I'll read through them again to see what typos slipped through.