Range

2moretypes/range.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"fmt"
+	"reflect"
+)
+
+func main() {
+	fmt.Println("Range form of the for loof iterates over a slice or map")
+	fmt.Println("When ranging over a slice, two values are returned for each iteration. The first is the index, and the second is a copy of the element at that index")
+
+	var primes = []int{2, 3, 5, 7, 11, 13, 17}
+
+	fmt.Printf("%p, %p, %p, %p\n", &primes, primes, &primes[0], &primes[1])
+	fmt.Printf("%s, %s, %s\n\n", reflect.TypeOf(primes).Kind(), reflect.TypeOf(&primes).Kind(), reflect.TypeOf(&primes[0]).Kind())
+
+	for i, v := range primes {
+		fmt.Printf("%d: %d\n", i, v)
+		fmt.Printf("POINTER: %p\n\n", &v) // v is just a copy !!!
+		v = 10                            // This line has NO impact
+	}
+	fmt.Println(primes)
+
+	fmt.Printf("\n\n")
+	fmt.Println("You can skip the index OR value by assigning to _")
+
+	// for i, _ := range varname
+	// for _, value := range varname
+
+	pow := make([]int, 10)
+	for i := range pow { // i is INDEX here! not value of pow!!!
+		pow[i] = 1 << i
+	}
+
+	for _, value := range pow {
+		fmt.Printf("%d\n", value)
+	}
+
+}