Array Diff - 20 Jun 2013
For one of my side projects, I wanted to find the differences between two arrays. I needed to know what additions/deletions to make on one array to recreate the other.
Here’s the solution I came up with:
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| class ArrayDiff | |
| attr_reader :one, :two | |
| def initialize one, two | |
| @one, @two = one.to_a, two.to_a | |
| end | |
| def deletions | |
| one_dup = one.clone | |
| two.each { |x| one_dup.slice!(one_dup.index(x)) if one_dup.index(x) } | |
| one_dup | |
| end | |
| def additions | |
| two_dup = two.clone | |
| one.each { |x| two_dup.slice!(two_dup.index(x)) if two_dup.index(x) } | |
| two_dup | |
| end | |
| end | |
| describe ArrayDiff do | |
| let(:array_diff) { ArrayDiff.new [1, 2, 2, 3, 6, 6, 7, 7, 7], | |
| [2, 3, 3, 4, 8, 9] } | |
| describe '#deletions' do | |
| it 'returns array of deletions' do | |
| expect(array_diff.deletions).to eq [1, 2, 6, 6, 7, 7, 7] | |
| end | |
| end | |
| describe '#additions' do | |
| it 'returns array of additions' do | |
| expect(array_diff.additions).to eq [3, 4, 8, 9] | |
| end | |
| end | |
| end |