add: slices - first part

x-tba/strings-revisited/07-encoding-examples/main.go

@@ -0,0 +1,60 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+	"unicode/utf8"
+	"unsafe"
+)
+
+func main() {
+	// try yourself: try other runes!
+	// you can find more here: https://unicode-table.com
+	// r := '🙉'
+
+	// r := '\u011e'
+	r := 'Ğ'
+
+	// only codepoint (can't be printed)
+	fmt.Printf("before encoding: %d\n", r)
+	fmt.Printf("  bits : %016b\n", r)
+	fmt.Printf("  bytes: % x\n", r)
+
+	// utf-8 encoded string
+	encoded := string(r)
+	encodedBytes := []byte(encoded)
+
+	fmt.Println()
+	fmt.Printf("after encoding: %q\n", encoded)
+	fmt.Printf("  bits : %8b\n", encodedBytes)
+	fmt.Printf("  bytes: % x\n", encodedBytes)
+
+	// utf-8 string efficient to store and transmit
+	//   but, it's harder to use.
+	//
+	// rune slice is inefficient.
+	//   but, it's easy to use.
+	fmt.Println()
+	fmt.Println("string (utf-8) vs []rune (unicode)")
+
+	s := "hava çok güzel 😳"
+	fmt.Printf("%q\n", s)
+	fmt.Printf("  size      : %d bytes\n", len(s))
+	fmt.Printf("  len       : %d chars\n", utf8.RuneCountInString(s))
+	fmt.Printf("  s[5]      : %q\n", s[5])
+	fmt.Printf("  s[5:7]    : %q\n", s[5:7])
+
+	runes := []rune(s)
+	size := int(unsafe.Sizeof(runes[0])) * len(runes)
+
+	fmt.Printf("\n%q\n", runes)
+	fmt.Printf("  size      : %d bytes\n", size)
+	fmt.Printf("  len       : %d chars\n", len(runes))
+	fmt.Printf("  runes[5]  : %q\n", runes[5])
+}