Merge pull request #567 from devlights/add-gocollective-examples

Author: devlights

examples/gocollective/check-if-map-contains-key/Taskfile.yml

@@ -0,0 +1,12 @@
+version: '3'
+
+tasks:
+  imports:
+    cmds:
+      - goimports -w .
+  vet:
+    cmds:
+      - go vet .
+  run:
+    cmds:
+      - go run -race main.go

examples/gocollective/check-if-map-contains-key/main.go

@@ -0,0 +1,32 @@
+// Stackoverflow Go Collective example
+//
+// How to check if a map contains a key in Go?
+//
+// URL
+//   - https://stackoverflow.com/questions/2050391/how-to-check-if-a-map-contains-a-key-in-go
+//
+// REFERENCES
+package main
+
+import "fmt"
+
+func main() {
+	// Goでmapに対象のキーがあるのかを確認するのは以下のようにする
+
+	var (
+		m = make(map[string]string)
+	)
+	m["hello"] = "world"
+
+	v, ok := m["hello"]
+	if !ok {
+		fmt.Printf("key '%s' does not exists.", "hello")
+	}
+	fmt.Println(v)
+
+	v, ok = m["world"]
+	if !ok {
+		fmt.Printf("key '%s' does not exists.", "world")
+	}
+	fmt.Println(v)
+}