test: add exmaple for maputil package

maputil/map_example_test.go

@@ -0,0 +1,181 @@
+package maputil
+
+import (
+	"fmt"
+	"sort"
+)
+
+func ExampleKeys() {
+	m := map[int]string{
+		1: "a",
+		2: "a",
+		3: "b",
+		4: "c",
+		5: "d",
+	}
+
+	keys := Keys(m)
+	sort.Ints(keys)
+
+	fmt.Println(keys)
+
+	// Output:
+	// [1 2 3 4 5]
+}
+
+func ExampleValues() {
+	m := map[int]string{
+		1: "a",
+		2: "a",
+		3: "b",
+		4: "c",
+		5: "d",
+	}
+
+	values := Values(m)
+	sort.Strings(values)
+
+	fmt.Println(values)
+
+	// Output:
+	// [a a b c d]
+}
+
+func ExampleMerge() {
+	m1 := map[int]string{
+		1: "a",
+		2: "b",
+	}
+	m2 := map[int]string{
+		1: "c",
+		3: "d",
+	}
+
+	result := Merge(m1, m2)
+
+	fmt.Println(result)
+
+	// Output:
+	// map[1:c 2:b 3:d]
+}
+
+func ExampleForEach() {
+	m := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 3,
+		"d": 4,
+	}
+
+	var sum int
+	ForEach(m, func(_ string, value int) {
+		sum += value
+	})
+
+	fmt.Println(sum)
+
+	// Output:
+	// 10
+}
+
+func ExampleFilter() {
+	m := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 3,
+		"d": 4,
+		"e": 5,
+	}
+
+	isEven := func(_ string, value int) bool {
+		return value%2 == 0
+	}
+
+	result := Filter(m, isEven)
+
+	fmt.Println(result)
+
+	// Output:
+	// map[b:2 d:4]
+}
+
+func ExampleIntersect() {
+	m1 := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 3,
+	}
+
+	m2 := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 6,
+		"d": 7,
+	}
+
+	m3 := map[string]int{
+		"a": 1,
+		"b": 9,
+		"e": 9,
+	}
+
+	result1 := Intersect(m1)
+	result2 := Intersect(m1, m2)
+	result3 := Intersect(m1, m2, m3)
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+	fmt.Println(result3)
+
+	// Output:
+	// map[a:1 b:2 c:3]
+	// map[a:1 b:2]
+	// map[a:1]
+}
+
+func ExampleMinus() {
+	m1 := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 3,
+	}
+
+	m2 := map[string]int{
+		"a": 11,
+		"b": 22,
+		"d": 33,
+	}
+
+	result := Minus(m1, m2)
+
+	fmt.Println(result)
+
+	// Output:
+	// map[c:3]
+}
+
+func ExampleIsDisjoint() {
+	m1 := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 3,
+	}
+
+	m2 := map[string]int{
+		"d": 22,
+	}
+
+	m3 := map[string]int{
+		"a": 22,
+	}
+
+	result1 := IsDisjoint(m1, m2)
+	result2 := IsDisjoint(m1, m3)
+
+	fmt.Println(result1)
+	fmt.Println(result2)
+
+	// Output:
+	// true
+	// false
+}