From 0bc3a54efddc331a98e3e25f64a1dc5ead6920bb Mon Sep 17 00:00:00 2001 From: Andy Long Date: Sun, 4 Sep 2022 08:21:31 +0100 Subject: [PATCH] Adding some new funky functions (#32) * Adding some new funky functions which I find useful Created a Tuple struct as some of the new functions require you to return a new slice with two fields which is the result of the new functions Created the Join, JoinProjection, Range, SumMap, Zip functions, ecah fuction is documented with how it works and had a unit test or maybe more * Added in an OrderBy function * Documentation comment for OrderBy which I missed out * Adding a Unit test for JoinProject function Updated the comments on the Join & OrderBy functions so they make a little more sense. Covered an extra test case with the Join test, where the left set has more data than the right and so the Right handside array of the join is empty --- .gitignore | 1 + join.go | 38 +++++++++++++++++++++++++++++ join_test.go | 45 ++++++++++++++++++++++++++++++++++ orderBy.go | 26 ++++++++++++++++++++ orderBy_test.go | 31 +++++++++++++++++++++++ range.go | 16 ++++++++++++ range_test.go | 24 ++++++++++++++++++ sum.go | 10 ++++++++ sum_test.go | 18 ++++++++++++++ tuple.go | 6 +++++ zip.go | 20 +++++++++++++++ zip_test.go | 65 +++++++++++++++++++++++++++++++++++++++++++++++++ 12 files changed, 300 insertions(+) create mode 100644 join.go create mode 100644 join_test.go create mode 100644 orderBy.go create mode 100644 orderBy_test.go create mode 100644 range.go create mode 100644 range_test.go create mode 100644 tuple.go create mode 100644 zip.go create mode 100644 zip_test.go diff --git a/.gitignore b/.gitignore index 0fd6007..804df32 100644 --- a/.gitignore +++ b/.gitignore @@ -59,3 +59,4 @@ Temporary Items .apdisk docs/public .trivycache/ +.vscode/launch.json diff --git a/join.go b/join.go new file mode 100644 index 0000000..c681015 --- /dev/null +++ b/join.go @@ -0,0 +1,38 @@ +package underscore + +// Joins two slices together and returns a Tuple of [T, []P], the selectors allow you to pick the +// keys you want to use from your struct's to join the sets together +func Join[T, P any, S comparable]( + left []T, + right []P, + leftSelector func(T) S, + rightSelector func(P) S) []Tuple[T, []P] { + + var results = make([]Tuple[T, []P], 0, len(left)) + for _, l := range left { + var matches = Filter(right, func(r P) bool { return leftSelector(l) == rightSelector(r) }) + var tuple = Tuple[T, []P]{Left: l, Right: matches} + results = append(results, tuple) + } + + return results +} + +// Joins two slices together and returns a []O where O is defined by the output +// of your projection function +// The selectors allow you to pick the keys from your structure to use as the join keys +// While the projection functions allows you to reformat joined datasets +// (Tuple of [T, []P]) into your own struct or type +func JoinProject[L, R, O any, S comparable]( + left []L, + right []R, + leftSelector func(L) S, + rightSelector func(R) S, + projection func(Tuple[L, []R]) O) (results []O) { + + for _, x := range Join(left, right, leftSelector, rightSelector) { + results = append(results, projection(x)) + } + + return results +} diff --git a/join_test.go b/join_test.go new file mode 100644 index 0000000..1159af5 --- /dev/null +++ b/join_test.go @@ -0,0 +1,45 @@ +package underscore_test + +import ( + "testing" + + u "github.com/rjNemo/underscore" + "github.com/stretchr/testify/assert" +) + +var zero = u.Tuple[int, string]{Left: 0, Right: "Zero"} +var one = u.Tuple[int, string]{Left: 1, Right: "One"} +var two = u.Tuple[int, string]{Left: 2, Right: "Two"} +var three = u.Tuple[int, string]{Left: 3, Right: "Three"} + +func Test_Join_Can_Join_Two_Slices_Together(t *testing.T) { + var left = []u.Tuple[int, string]{zero, one, two, three} + var right = []u.Tuple[int, string]{one, three, two, three, two, three} + + selector := func(x u.Tuple[int, string]) int { return x.Left } + + var joined = u.Join(left, right, selector, selector) + var want = []u.Tuple[u.Tuple[int, string], []u.Tuple[int, string]]{ + {Left: zero, Right: nil}, + {Left: one, Right: []u.Tuple[int, string]{one}}, + {Left: two, Right: []u.Tuple[int, string]{two, two}}, + {Left: three, Right: []u.Tuple[int, string]{three, three, three}}, + } + + assert.Equal(t, want, joined) +} + +func Test_Join_Can_Join_and_Project_Two_Slices_Together(t *testing.T) { + var left = []u.Tuple[int, string]{zero, one, two, three} + var right = []u.Tuple[int, string]{one, three, two, three, two, three} + + selector := func(x u.Tuple[int, string]) int { return x.Left } + project := func(x u.Tuple[u.Tuple[int, string], []u.Tuple[int, string]]) int { + return len(x.Right) // projecting to a could of how many + } + + var joined = u.JoinProject(left, right, selector, selector, project) + var want = []int{0, 1, 2, 3} + + assert.Equal(t, want, joined) +} diff --git a/orderBy.go b/orderBy.go new file mode 100644 index 0000000..8ee7671 --- /dev/null +++ b/orderBy.go @@ -0,0 +1,26 @@ +package underscore + +// Orders a slice by a field value within a struct, the predicate allows you +// to pick the fields you want to orderBy. Use > for ASC or < for DESC +// func (left Person, right Person) bool { return left.Age > right.Age } +func OrderBy[T any](list []T, predicate func(T, T) bool) []T { + swaps := true + var tmp T + + //todo: replace with a faster algorithm, this one is pretty simple + for swaps { + swaps = false + + for i := 0; i < len(list)-1; i++ { + if predicate(list[i], list[i+1]) { + swaps = true + tmp = list[i] + + list[i] = list[i+1] + list[i+1] = tmp + } + } + } + + return list +} diff --git a/orderBy_test.go b/orderBy_test.go new file mode 100644 index 0000000..ac0d802 --- /dev/null +++ b/orderBy_test.go @@ -0,0 +1,31 @@ +package underscore_test + +import ( + "testing" + + "github.com/stretchr/testify/assert" + + u "github.com/rjNemo/underscore" +) + +func Test_OrderBy_Asc(t *testing.T) { + set := u.Range(5, 0) + want := u.Range(0, 5) + + result := u.OrderBy(set, func(left int, right int) bool { + return left > right + }) + + assert.Equal(t, want, result) +} + +func Test_OrderBy_Desc(t *testing.T) { + set := u.Range(0, 5) + want := u.Range(5, 0) + + result := u.OrderBy(set, func(left int, right int) bool { + return left < right + }) + + assert.Equal(t, want, result) +} diff --git a/range.go b/range.go new file mode 100644 index 0000000..204c6b8 --- /dev/null +++ b/range.go @@ -0,0 +1,16 @@ +package underscore + +// Creates a sequence of numbers, i.e. u.Range(0, 3) = [0 1 2 3], while u.Range(3, 0) = [3 2 1 0] +func Range(start int, end int) (result []int) { + if start < end { + for i := start; i <= end; i++ { + result = append(result, i) + } + } else { + for i := start; i >= end; i-- { + result = append(result, i) + } + } + + return result +} diff --git a/range_test.go b/range_test.go new file mode 100644 index 0000000..f59ee5c --- /dev/null +++ b/range_test.go @@ -0,0 +1,24 @@ +package underscore_test + +import ( + "reflect" + "testing" + + u "github.com/rjNemo/underscore" +) + +func Test_Range_Creates_Slices(t *testing.T) { + range1 := u.Range(0, 5) + want1 := []int{0, 1, 2, 3, 4, 5} + + if !reflect.DeepEqual(range1, want1) { + t.Errorf("Expected the result to be %v but we got %v", want1, range1) + } + + range2 := u.Range(5, 0) + want2 := []int{5, 4, 3, 2, 1, 0} + + if !reflect.DeepEqual(range2, want2) { + t.Errorf("Expected the result to be %v but we got %v", want2, range2) + } +} diff --git a/sum.go b/sum.go index 3d2b5db..0cc9652 100644 --- a/sum.go +++ b/sum.go @@ -9,3 +9,13 @@ func Sum[T constraints.Ordered](values []T) (sum T) { } return sum } + +// Sums the values you select from your struct, basically a sort cut instead of +// having to perform a u.Map followed by a u.Sum +func SumMap[T any, R constraints.Ordered](list []T, selector func(T) R) (sum R) { + for _, v := range list { + sum += selector(v) + } + + return sum +} diff --git a/sum_test.go b/sum_test.go index 05a2a8a..4d5556d 100644 --- a/sum_test.go +++ b/sum_test.go @@ -13,3 +13,21 @@ func TestSum(t *testing.T) { assert.Equal(t, want, u.Sum(nums)) } + +func TestSumMap(t *testing.T) { + nums := []u.Tuple[string, int]{ + {"zero", 0}, + {"one", 1}, + {"two", 2}, + {"three", 3}, + {"four", 4}, + {"five", 5}, + {"six", 6}, + {"seven", 7}, + {"eight", 8}, + {"nine", 9}, + } + want := 45 + + assert.Equal(t, want, u.SumMap(nums, func(item u.Tuple[string, int]) int { return item.Right })) +} diff --git a/tuple.go b/tuple.go new file mode 100644 index 0000000..a229f52 --- /dev/null +++ b/tuple.go @@ -0,0 +1,6 @@ +package underscore + +type Tuple[L, R any] struct { + Left L + Right R +} diff --git a/zip.go b/zip.go new file mode 100644 index 0000000..ca53e62 --- /dev/null +++ b/zip.go @@ -0,0 +1,20 @@ +package underscore + +// Zips two slices togther so all the elements of left slice are attached to the corresponding +// elements of the right slice, i.e. [one two three] [1 2 3 4] = [{one, 1} {two, 2} {three, 3}] +// the returned data will be the size of the smallest slice +func Zip[L any, R any](left []L, right []R) []Tuple[L, R] { + shortest := 0 + if len(left) < len(right) { + shortest = len(left) + } else { + shortest = len(right) + } + + results := make([]Tuple[L, R], shortest) + for i := 0; i < shortest; i++ { + results[i] = Tuple[L, R]{Left: left[i], Right: right[i]} + } + + return results +} diff --git a/zip_test.go b/zip_test.go new file mode 100644 index 0000000..66b8ddf --- /dev/null +++ b/zip_test.go @@ -0,0 +1,65 @@ +package underscore_test + +import ( + "reflect" + "testing" + + u "github.com/rjNemo/underscore" +) + +func Test_Zip_Can_Zip_Two_Equal_Sized_Slices(t *testing.T) { + left := []string{"Left 1", "Left 2", "Left 3"} + right := []int{1, 2, 3} + + var zipped = u.Zip(left, right) + + want := []u.Tuple[string, int]{ + {Left: "Left 1", Right: 1}, + {Left: "Left 2", Right: 2}, + {Left: "Left 3", Right: 3}, + } + + if !reflect.DeepEqual(zipped, want) { + t.Errorf("Expected the result to be %v but we got %v", want, zipped) + } +} + +func Test_Zip_Can_Zip_Two_Different_Sized_Slices_Left_Larger(t *testing.T) { + left := []string{"Left 1", "Left 2", "Left 3", "Left 4"} + right := []int{1, 2, 3} + + var zipped = u.Zip(left, right) + if len(zipped) != 3 { + t.Errorf("Expected the result of Zip(left, right) to have a length of 3 but got %v", len(zipped)) + } + + want := []u.Tuple[string, int]{ + {Left: "Left 1", Right: 1}, + {Left: "Left 2", Right: 2}, + {Left: "Left 3", Right: 3}, + } + + if !reflect.DeepEqual(zipped, want) { + t.Errorf("Expected the result to be %v but we got %v", want, zipped) + } +} + +func Test_Zip_Can_Zip_Two_Different_Sized_Slices_Right_Larger(t *testing.T) { + left := []string{"Left 1", "Left 2", "Left 3"} + right := []int{1, 2, 3, 4} + + var zipped = u.Zip(left, right) + if len(zipped) != 3 { + t.Errorf("Expected the result of Zip(left, right) to have a length of 3 but got %v", len(zipped)) + } + + want := []u.Tuple[string, int]{ + {Left: "Left 1", Right: 1}, + {Left: "Left 2", Right: 2}, + {Left: "Left 3", Right: 3}, + } + + if !reflect.DeepEqual(zipped, want) { + t.Errorf("Expected the result to be %v but we got %v", want, zipped) + } +}