starting go by example

5-go-by-example/10-maps.go

@@ -0,0 +1,36 @@
+package main
+
+import "fmt"
+
+// Maps are Go’s built-in associative data type
+func main() {
+
+	// create an empty map, use the builtin: make(map[key-type]val-type).
+	m := make(map[string]int)
+
+	// set key/value pairs using typical name[key]=val syntax
+	m["k1"] = 7
+	m["k2"] = 13
+
+	// printing a map will show all of its key/value pairs
+	fmt.Println("map:", m)
+
+	// get a value for a key with name[key]
+	v1 := m["k1"]
+	fmt.Println("v1: ", v1)
+
+	// len returns the number of key/value pairs
+	fmt.Println("len:", len(m))
+
+	// delete removes key/value pairs
+	delete(m, "k2")
+	fmt.Println("map:", m)
+
+	// optional second return value when getting a value from a map indicates if the key was present in the map
+	_, prs := m["k2"]
+	fmt.Println("prs:", prs)
+
+	// declare and initialize a new map in the same line
+	n := map[string]int{"foo": 1, "bar": 2}
+	fmt.Println("map:", n)
+}