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swap! #3

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merged 1 commit into from
Sep 28, 2015
Merged

swap! #3

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20 changes: 19 additions & 1 deletion src/IndexedArrays.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,24 @@ end

copy{T}(ia::IndexedArray{T}) = IndexedArray{T}(copy(ia.items))

export AbstractIndexedArray, IndexedArray, IndexedArrayError, findfirst!
"`swap!(ia::IndexedArray, to::Int, from::Int)` interchange/swap the values on the indices `to` and `from` in the `IndexedArray`"
function swap!(ia::IndexedArray, to::Int, from::Int)
if to == from
checkbounds(ia,to)
return ia
end
previous_id = ia[to]
future_id = ia[from]

ia.items[to] = future_id
ia.items[from] = previous_id

ia.lookup[previous_id] = from
ia.lookup[future_id] = to

return ia
end

export AbstractIndexedArray, IndexedArray, IndexedArrayError, findfirst!, swap!

end # module
17 changes: 17 additions & 0 deletions test/runtests.jl
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Expand Up @@ -53,6 +53,23 @@ ia2 = copy(ia)
@test ia2[:] == ["cat", "dog", "mouse"]
@test findfirst(ia2, "cat") == 1

let ia = IndexedArray(["cat", "dog", "mouse", "human"]), original = copy(ia)

ia = swap!(ia, 2, 2)

@test ia == original
@test_throws BoundsError swap!(ia, 5, 5)

swap!(ia, 2, 3)

@test findfirst(ia, "mouse") == 2
@test findfirst(original, "mouse") == 3

@test findfirst(ia, "dog") == 3
@test findfirst(original, "dog") == 2
end


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Thanks! Can you switch to a four-space indent and also get rid of the added newline at the end of the file?

I think it would also be good to have a test for when to == from. Perhaps the function itself should special-case for this and return immediately as well.

# setindex!

# indexin, findin
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