Initial Commit

go/etl/README.md

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+# Etl
+
+We are going to do the `Transform` step of an Extract-Transform-Load.
+
+### ETL
+Extract-Transform-Load (ETL) is a fancy way of saying, "We have some crufty, legacy data over in this system, and now we need it in this shiny new system over here, so
+we're going to migrate this."
+
+(Typically, this is followed by, "We're only going to need to run this
+once." That's then typically followed by much forehead slapping and
+moaning about how stupid we could possibly be.)
+
+### The goal
+We're going to extract some scrabble scores from a legacy system.
+
+The old system stored a list of letters per score:
+
+- 1 point: "A", "E", "I", "O", "U", "L", "N", "R", "S", "T",
+- 2 points: "D", "G",
+- 3 points: "B", "C", "M", "P",
+- 4 points: "F", "H", "V", "W", "Y",
+- 5 points: "K",
+- 8 points: "J", "X",
+- 10 points: "Q", "Z",
+
+The shiny new scrabble system instead stores the score per letter, which
+makes it much faster and easier to calculate the score for a word. It
+also stores the letters in lower-case regardless of the case of the
+input letters:
+
+- "a" is worth 1 point.
+- "b" is worth 3 points.
+- "c" is worth 3 points.
+- "d" is worth 2 points.
+- Etc.
+
+Your mission, should you choose to accept it, is to write a program that
+transforms the legacy data format to the shiny new format.
+
+### Notes
+Note that both the old and the new system use strings to represent
+letters, even in languages that have a separate data type for
+characters.
+
+A final note about scoring, Scrabble is played around the world in a
+variety of languages, each with its own unique scoring table. For
+example, an "A" is scored at 14 in the Basque-language version of the
+game while being scored at 9 in the Latin-language version.
+
+To run the tests simply run the command `go test` in the exercise directory.
+
+If the test suite contains benchmarks, you can run these with the `-bench`
+flag:
+
+    go test -bench .
+
+For more detailed info about the Go track see the [help
+page](http://help.exercism.io/getting-started-with-go.html).
+
+## Source
+
+The Jumpstart Lab team [view source](http://jumpstartlab.com)

go/etl/etl.go

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+package etl
+
+import "strings"
+
+// Transform takes the legacy data structure
+// and converts it into the new and improved
+// data structure oh man this new system will
+// make us so rich you guys.
+func Transform(input map[int][]string) map[string]int {
+	ret := make(map[string]int)
+	for k, v := range input {
+		for _, let := range v {
+			ret[strings.ToLower(let)] = k
+		}
+	}
+	return ret
+}

go/etl/etl_test.go

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+package etl
+
+import "testing"
+
+type given map[int][]string
+type expectation map[string]int
+
+var transformTests = []struct {
+	input  given
+	output expectation
+}{
+	{
+		given{1: {"A"}},
+		expectation{"a": 1},
+	},
+	{
+		given{1: {"A", "E", "I", "O", "U"}},
+		expectation{"a": 1, "e": 1, "i": 1, "o": 1, "u": 1},
+	},
+	{
+		given{
+			1: {"A", "E"},
+			2: {"D", "G"},
+		},
+		expectation{
+			"a": 1,
+			"e": 1,
+			"d": 2,
+			"g": 2,
+		},
+	},
+	{
+		given{
+			1:  {"A", "E", "I", "O", "U", "L", "N", "R", "S", "T"},
+			2:  {"D", "G"},
+			3:  {"B", "C", "M", "P"},
+			4:  {"F", "H", "V", "W", "Y"},
+			5:  {"K"},
+			8:  {"J", "X"},
+			10: {"Q", "Z"},
+		},
+		expectation{
+			"a": 1, "e": 1, "i": 1, "o": 1, "u": 1, "l": 1, "n": 1, "r": 1, "s": 1, "t": 1,
+			"d": 2, "g": 2,
+			"b": 3, "c": 3, "m": 3, "p": 3,
+			"f": 4, "h": 4, "v": 4, "w": 4, "y": 4,
+			"k": 5,
+			"j": 8, "x": 8,
+			"q": 10, "z": 10,
+		},
+	},
+}
+
+func equal(actual map[string]int, expectation map[string]int) bool {
+	if len(actual) != len(expectation) {
+		return false
+	}
+
+	for k, actualVal := range actual {
+		expectationVal, present := expectation[k]
+
+		if !present || actualVal != expectationVal {
+			return false
+		}
+	}
+
+	return true
+}
+
+func TestTranform(t *testing.T) {
+	for _, tt := range transformTests {
+		actual := Transform(map[int][]string(tt.input))
+		if !equal(actual, tt.output) {
+			t.Fatalf("Transform(%v). Expected [%v], Actual [%v]", tt.input, tt.output, actual)
+		}
+	}
+}
+
+func BenchmarkTranform(b *testing.B) {
+	b.StopTimer()
+	for _, tt := range transformTests {
+		b.StartTimer()
+
+		for i := 0; i < b.N; i++ {
+			Transform(map[int][]string(tt.input))
+		}
+
+		b.StopTimer()
+	}
+}