Learn Go - Primitives Summary

primitives.go

// Primitives Examples
package main

import "fmt"

func main() {
	var n bool = true
	var m bool // zero value is false
	fmt.Printf("%v, %T\n", n, n)
	fmt.Printf("%v, %T\n", m, m)

	o := 42 // basic int type, at least 32 bits
	// other options are below (SIGNED)
	// int8 (-128 to +127)
	// int16
	// int32
	// int64
	var p uint16 = 42
	fmt.Printf("%v, %T\n", o, o)
	fmt.Printf("%v, %T\n", p, p)

	// unsigned integers include
	// uint8 (0 to 255)
	// uint16
	// uint32
	// byte (alias for uint8, just because they are so common)

	// basic arithmetic options exist, but an only do arithmetic on same types
	var a int = 10
	var b int8 = 3
	fmt.Println(a + int(b))

	var c byte = 10     // 00001010
	var d byte = 3      // 00000011
	fmt.Println(c & d)  // 00000010
	fmt.Println(c | d)  // 00001011
	fmt.Println(c ^ d)  // 00001001
	fmt.Println(c &^ d) // 0100
	fmt.Println(d << 3)
	fmt.Println(d >> 3)

	f := 3.14 // will always be float64, but you can use float32 too
	fmt.Println(f)
	f = 13.7e10
	fmt.Println(f)

	var g complex64 = 1 + 2i
	fmt.Printf("%v, %T\n", g, g)
	fmt.Printf("%v, %T\n", real(g), real(g)) // complex64 decomposes to float32s
	fmt.Printf("%v, %T\n", imag(g), imag(g)) // complex128 decomposes to float64s

	s := "this is a string" // strings are immutable
	fmt.Printf("%v, %T\n", s, s)
	fmt.Printf("%v, %T\n", s[2], s[2]) // strings are alias's for bytes
	fmt.Printf("%v, %T\n", string(s[2]), string(s[2]))

	// convert to a slice of bytes
	t := []byte(s) // "collection" of "byte"s, string s
	fmt.Printf("%v, %T\n", t, t)

	// runes are unicode 32 vs strings are unicode 8
	u := 'a'
	fmt.Printf("%v, %T\n", u, u)

}