Merge pull request #3 from 0bvim/feat/section15

feat/section15

src/udemy/go_ted/section15/main.go

@@ -0,0 +1,64 @@
+package main
+
+import "fmt"
+
+func main() {
+
+	mapping := map[string]int{
+		"Todd":  42,
+		"Lila":  22,
+		"Stete": 32,
+	}
+	// 116 - map
+	{
+		fmt.Printf("mapping: %v\n", mapping)
+		fmt.Printf("mapping Lila: %v\n", mapping["Lila"])
+
+		another := make(map[string]int)
+		another["Lucas"] = 28
+		another["Steph"] = 37
+		fmt.Printf("another: %v\n", another)
+		fmt.Println("--------------")
+	}
+	// 117 adding element in a map and using range
+	{
+		for key, value := range mapping {
+			fmt.Println(key, value)
+		}
+
+		for _, value := range mapping {
+			fmt.Println(value)
+		}
+
+		for key, _ := range mapping {
+			fmt.Println(key)
+		}
+		fmt.Println("--------------")
+	}
+	// 118 delete item from a map
+	{
+		delete(mapping, "Todd")
+		delete(mapping, "Todd") // using twice don't make program panic, just ignore even if you try to print or something else.
+
+		fmt.Printf("mapping: %v\n", mapping["Todd"])
+		fmt.Printf("mapping: %v\n", mapping)
+		fmt.Println("--------------")
+	}
+	// 118 using ok notation to verify valid values in map
+	{
+		// if you liik up a non-existent key, the zero value will be returned as the value associated
+		// with that non-existent key
+		if v, ok := mapping["Lila"]; !ok {
+			fmt.Println("key didn't exist")
+		} else {
+			fmt.Println(v)
+		}
+
+		delete(mapping, "Lila")
+		if v, ok := mapping["Lila"]; ok {
+			fmt.Println(v)
+		} else {
+			fmt.Println("key didn't exist")
+		}
+	}
+}