feat(Go-Tool)：2020/11/12:新增linq包使用示例(未完成)

vendor/github.com/ahmetalpbalkan/go-linq/take.go

@@ -0,0 +1,84 @@
+package linq
+
+// Take returns a specified number of contiguous elements from the start of a collection.
+func (q Query) Take(count int) Query {
+	return Query{
+		Iterate: func() Iterator {
+			next := q.Iterate()
+			n := count
+
+			return func() (item interface{}, ok bool) {
+				if n <= 0 {
+					return
+				}
+
+				n--
+				return next()
+			}
+		},
+	}
+}
+
+// TakeWhile returns elements from a collection as long as a specified condition is true,
+// and then skips the remaining elements.
+func (q Query) TakeWhile(predicate func(interface{}) bool) Query {
+	return Query{
+		Iterate: func() Iterator {
+			next := q.Iterate()
+			done := false
+
+			return func() (item interface{}, ok bool) {
+				if done {
+					return
+				}
+
+				item, ok = next()
+				if !ok {
+					done = true
+					return
+				}
+
+				if predicate(item) {
+					return
+				}
+
+				done = true
+				return nil, false
+			}
+		},
+	}
+}
+
+// TakeWhileIndexed returns elements from a collection as long as a specified condition
+// is true. The element's index is used in the logic of the predicate function.
+// The first argument of predicate represents the zero-based index of the element
+// within collection. The second argument represents the element to test.
+func (q Query) TakeWhileIndexed(predicate func(int, interface{}) bool) Query {
+	return Query{
+		Iterate: func() Iterator {
+			next := q.Iterate()
+			done := false
+			index := 0
+
+			return func() (item interface{}, ok bool) {
+				if done {
+					return
+				}
+
+				item, ok = next()
+				if !ok {
+					done = true
+					return
+				}
+
+				if predicate(index, item) {
+					index++
+					return
+				}
+
+				done = true
+				return nil, false
+			}
+		},
+	}
+}