From 4c1496b6481e1b022d01091222c02290f6e2a3d1 Mon Sep 17 00:00:00 2001
From: dudaodong <lanliddd.2007@163.com>
Date: Fri, 17 Feb 2023 11:57:09 +0800
Subject: [PATCH] feat: add FilterByKeys function

---
 maputil/map.go      | 19 ++++++++++++++++++-
 maputil/map_test.go | 19 +++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/maputil/map.go b/maputil/map.go
index 6c68811..1fa8451 100644
--- a/maputil/map.go
+++ b/maputil/map.go
@@ -4,7 +4,11 @@
 // Package maputil includes some functions to manipulate map.
 package maputil
 
-import "reflect"
+import (
+	"reflect"
+
+	"github.com/duke-git/lancet/v2/slice"
+)
 
 // Keys returns a slice of the map's keys.
 // Play: https://go.dev/play/p/xNB5bTb97Wd
@@ -93,6 +97,19 @@ func Filter[K comparable, V any](m map[K]V, predicate func(key K, value V) bool)
 	return result
 }
 
+// FilterByKeys iterates over map, return a new map whose keys are all given keys.
+// todo:
+func FilterByKeys[K comparable, V any](m map[K]V, keys []K) map[K]V {
+	result := make(map[K]V)
+
+	for k, v := range m {
+		if slice.Contain(keys, k) {
+			result[k] = v
+		}
+	}
+	return result
+}
+
 // Intersect iterates over maps, return a new map of key and value pairs in all given maps.
 // Play: https://go.dev/play/p/Zld0oj3sjcC
 func Intersect[K comparable, V any](maps ...map[K]V) map[K]V {
diff --git a/maputil/map_test.go b/maputil/map_test.go
index b101d48..b2007d1 100644
--- a/maputil/map_test.go
+++ b/maputil/map_test.go
@@ -149,6 +149,25 @@ func TestFilter(t *testing.T) {
 	}, acturl)
 }
 
+func TestFilterByKeys(t *testing.T) {
+	assert := internal.NewAssert(t, "TestFilterByKeys")
+
+	m := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 3,
+		"d": 4,
+		"e": 5,
+	}
+
+	acturl := FilterByKeys(m, []string{"a", "b"})
+
+	assert.Equal(map[string]int{
+		"a": 1,
+		"b": 2,
+	}, acturl)
+}
+
 func TestIntersect(t *testing.T) {
 	assert := internal.NewAssert(t, "TestIntersect")