monads

commit d86519fe954cbeef88ccd1c96f611aeb908389d9
parent c4c0fd180a4b2b0c6986d61fa64f4fb2fbc40d24
Author: Yongbin Kim <iam@yongbin.kim>
Date:   Thu, 29 Sep 2022 14:12:03 +0900

slices: feat: Added two select methods.

Select finds item from slice. It works like `Filter` function, but
instead of returning every matched item, it returns the first one.

SelectFirst finds from beginning of slice, SelectLast is from last.

Signed-off-by: Yongbin Kim <iam@yongbin.kim>

Diffstat:
A
slices/select.go
 | 
24
++++++++++++++++++++++++

1 file changed, 24 insertions(+), 0 deletions(-)
diff --git a/slices/select.go b/slices/select.go
@@ -0,0 +1,24 @@
+package slices
+
+// SelectFirst finds a item from beginning of slice and returns the first
+// matched item.
+func SelectFirst[T any](items []T, action func(T) bool) (result T, ok bool) {
+	for _, item := range items {
+		if action(item) {
+			return item, true
+		}
+	}
+	return
+}
+
+// SelectLast finds a item from ending of slice and returns the first
+// matched item.
+func SelectLast[T any](items []T, action func(T) bool) (result T, ok bool) {
+	for i := len(items) - 1; i >= 0; i-- {
+		item := items[i]
+		if action(item) {
+			return item, true
+		}
+	}
+	return
+}