day 8 work and jumbled together

utils/arrays/arrays.go

@@ -0,0 +1,49 @@
+package arrays
+
+func FindFirst(list []string, filter func(string) bool) string {
+	for _, item := range list {
+		if filter(item) {
+			return item
+		}
+	}
+	panic("No item found that matches criteria")
+}
+
+func FindFirstInt(list []int, filter func(int) bool) int {
+	for _, item := range list {
+		if filter(item) {
+			return item
+		}
+	}
+	panic("No item found that matches criteria")
+}
+
+func FindAll(list []string, filter func(string) bool) []string {
+	var filteredList []string
+	for _, item := range list {
+		if filter(item) {
+			filteredList = append(filteredList, item)
+		}
+	}
+
+	return filteredList
+}
+
+func FindAllInt(list []int, filter func(int) bool) []int {
+	var filteredList []int
+	for _, item := range list {
+		if filter(item) {
+			filteredList = append(filteredList, item)
+		}
+	}
+
+	return filteredList
+}
+
+func MapStrToInt(input []string, fn func(string) int) []int {
+	var retVals []int
+	for _, s := range input {
+		retVals = append(retVals, fn(s))
+	}
+	return retVals
+}

utils/arrays/arrays_test.go

@@ -0,0 +1,47 @@
+package arrays
+
+import (
+	"AoC2021/utils/assert"
+	"testing"
+)
+
+func TestFindFirst(t *testing.T) {
+	list := []string{"foo", "bar", "baz"}
+	filter := func(s string) bool { return s == "baz" }
+	item := FindFirst(list, filter)
+
+	assert.EqualsStr(t, item, "baz", "should find item baz")
+}
+
+func TestFindFirstInt(t *testing.T) {
+	list := []int{1, 3, 4, 5}
+	filter := func(i int) bool { return i%2 == 0 }
+	item := FindFirstInt(list, filter)
+
+	assert.EqualsInt(t, item, 4, "should find even number")
+}
+
+func TestFindAll(t *testing.T) {
+	list := []string{"hello", "world", "foo"}
+	filter := func(s string) bool { return len(s) > 3 }
+	items := FindAll(list, filter)
+
+	assert.EqualsInt(t, len(items), 2, "should filter lists of strings")
+}
+
+func TestFindAllInt(t *testing.T) {
+	list := []int{1, 3, 99, 200, 9000}
+	filter := func(i int) bool { return i > 50 }
+	items := FindAllInt(list, filter)
+
+	assert.EqualsInt(t, len(items), 3, "should filter lists of ints")
+}
+
+func TestMapStrToInt(t *testing.T) {
+	list := []string{"alice", "bob", "carol"}
+	mapFn := func(s string) int { return int(s[0]) }
+
+	items := MapStrToInt(list, mapFn)
+
+	assert.EqualsInt(t, items[0], int('a'), "should run map function across all strings")
+}