edf50fdf80
- Run mix credo --all to identify possible code optimizations - Resolve most of the errors generated by credo such as: - Numbers larger than 9999 should be written with underscores: 58_127 - Modules should have a @moduledoc tag - Comparison will always return true
33 lines
1.1 KiB
Elixir
33 lines
1.1 KiB
Elixir
defmodule Comprehensions do
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@moduledoc false
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use Koans
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@intro "A comprehension is made of three parts: generators, filters, and collectibles. We will look at how these interact with each other"
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koan "The generator, `n <- [1, 2, 3, 4]`, is providing the values for our comprehension" do
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assert for(n <- [1, 2, 3, 4], do: n * n) == ___
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end
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koan "Any enumerable can be a generator" do
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assert for(n <- 1..4, do: n * n) == ___
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end
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koan "A generator specifies how to extract values from a collection" do
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collection = [["Hello", "World"], ["Apple", "Pie"]]
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assert for([a, b] <- collection, do: "#{a} #{b}") == ___
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end
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koan "You can use multiple generators at once" do
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assert for(x <- ["little", "big"], y <- ["dogs", "cats"], do: "#{x} #{y}") == ___
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end
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koan "Use a filter to reduce your work" do
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assert for(n <- [1, 2, 3, 4, 5, 6], n > 3, do: n) == ___
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end
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koan "Add the result of a comprehension to an existing collection" do
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collection = for x <- ["Pecan", "Pumpkin"], into: %{}, do: {x, "#{x} Pie"}
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assert collection == ___
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end
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end
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