initial commit

strings-and-runes/stringsandrunes.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"fmt"
+	"unicode/utf8"	
+)
+
+func main() {
+	// s is a string assigned a literal value representing the
+	// word "hello" in the Thai language.
+	// Go string literals are UTF-8 encoded text.
+	const s = "สวัสดี"
+	//Since strings are equivalent to []byte,
+	//this will produce the length of the raw bytes stored within
+	fmt.Println("len:", len(s))
+
+	// indexing into a string produces the raw byte values at each index.
+	// This loop generates the hex values of all the bytes
+	// that constitute the code points in s.
+	for i := 0; i < len(s); i++ {
+		fmt.Printf("%x ", s[i])
+	}
+	fmt.Println()
+	// To count how many runes are in a string,
+	// we ca can use the utf8 package. Note that
+	// the run-time of RuneCountInString depends on the size of the string
+	// due to having to decode each rune sequentially.
+	// Some Thai characters are represented by multiple UTF-8 code points,
+	// so the result of this count may be suprising.
+	fmt.Println("Rune count:",utf8.RuneCountInString(s))
+	// A range loop handles strings specially and decodes each rune
+	// along with it's offset in the string
+	for idx, runeValue := range s {
+		fmt.Printf("%#U Starts at %d\n", runeValue, idx)
+	}
+	//we can achieve the same iteration by using the utf8.DecodeRuneInString function explicitly
+	fmt.Println("\nUsing DecodeRuneInString")
+	for i,w := 0,0; i < len(s); i += w {
+		runeValue, width := utf8.DecodeRuneInString(s[i:])
+		fmt.Printf("%#U starts at %d\n", runeValue, i)
+		w = width
+		// This demonstrates passing a rune to a func
+		examineRune(runeValue)
+	}
+}
+
+// Values enclosed in single quotes are rune literals.
+// we can compare a rune value to a rune literal directly.
+func examineRune(r rune) {
+	if r == 't' {
+		fmt.Println("found tee")
+	} else if r == 'ส' {
+		fmt.Println("found so sua")
+	}
+}