Merge branch 'main' of https://github.com/rjNemo/underscore

Author: rjNemo

.gitignore

@@ -59,3 +59,4 @@ Temporary Items
 .apdisk
 docs/public
 .trivycache/
+.vscode/launch.json

count.go

@@ -0,0 +1,13 @@
+package underscore
+
+// Count returns the number of elements in the slice that satisfy the predicate.
+// example: Count([]int{1,2,3,4,5}, func(n int) bool { return n%2 == 0 }) // 2
+func Count[T comparable](slice []T, predicate func(T) bool) int {
+	count := 0
+	for _, item := range slice {
+		if predicate(item) {
+			count++
+		}
+	}
+	return count
+}

count_test.go

@@ -0,0 +1,64 @@
+package underscore
+
+import (
+	"github.com/stretchr/testify/assert"
+	"strings"
+	"testing"
+)
+
+func Test_Count_Can_Count_Numbers(t *testing.T) {
+	numbers := Range(1, 100)
+	count := Count(numbers, func(n int) bool {
+		return n%2 == 0
+	})
+
+	assert.Equal(t, 50, count)
+}
+
+type People struct {
+	Name   string
+	Age    int
+	Gender string
+}
+
+func Test_Count_Can_Count__People(t *testing.T) {
+	people := []People{
+		{Name: "Andy", Age: 43, Gender: "M"},
+		{Name: "Fred", Age: 33, Gender: "M"},
+		{Name: "Jack", Age: 23, Gender: "M"},
+		{Name: "Jill", Age: 43, Gender: "F"},
+		{Name: "Anna", Age: 33, Gender: "F"},
+		{Name: "Arya", Age: 23, Gender: "F"},
+		{Name: "Jane", Age: 13, Gender: "F"},
+	}
+
+	a := Count(people, func(p People) bool {
+		return strings.HasPrefix(p.Name, "A")
+	})
+	assert.Equal(t, 3, a)
+
+	females := Count(people, func(p People) bool {
+		return p.Gender == "F"
+	})
+	assert.Equal(t, 4, females)
+
+	males := Count(people, func(p People) bool {
+		return p.Gender == "M"
+	})
+	assert.Equal(t, 3, males)
+
+	over30 := Count(people, func(p People) bool {
+		return p.Age > 30
+	})
+	assert.Equal(t, 4, over30)
+
+	under30 := Count(people, func(p People) bool {
+		return p.Age < 30
+	})
+	assert.Equal(t, 3, under30)
+
+	under20 := Count(people, func(p People) bool {
+		return p.Age < 20
+	})
+	assert.Equal(t, 1, under20)
+}

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
+}

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)
+}

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
+}

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)
+}

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
+}

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)
+	}
+}

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
+}