initial commit

range/range.go

@@ -0,0 +1,37 @@
+package main
+
+import "fmt"
+
+func main(){
+	//here we use range to sum the numbers in a slice
+	nums := []int{2,3,4}
+	sum := 0
+	for _,num := range nums {
+		sum += num
+	}
+	fmt.Println("sum:",sum)
+
+	//range on arrays and slices provides both the index and value
+	// at each entry. above we didn't need the index, so we ignored it with the blank identifier
+	// but if we want the index we can use it like bellow
+	for i, num := range nums {
+		if num == 3 {
+			fmt.Println("index:",i)
+		}
+	}
+	//range on map iterates over the key value pairs.
+	kvs := map[string]string{"a":"apple","b":"banana"}
+	for k,v := range kvs{
+		fmt.Printf("%s -> %s\n",k,v)
+	}
+	//range can also iterate over just the keys of a map
+	for k := range kvs{
+		fmt.Println("key:",k)
+	}
+	// range on strings iterates over Unicode code points.
+	// the first value is the starting byte index of the rune
+	//and the second is the rune itself.
+	for i,c := range "go"{
+		fmt.Println(i,c)
+	}
+}