raw string

codes:

package main

func main() {
    raw := `Hello,
World
    !`

    println(raw)
}

output:

Hello,
World
	!

same string

codes:

package main

func main() {

    str1 := "日本語"                                  // UTF-8 input text
    str2 := `日本語`                                  // UTF-8 input text as a raw literal
    str3 := "\u65e5\u672c\u8a9e"                   // the explicit Unicode code points
    str4 := "\U000065e5\U0000672c\U00008a9e"       // the explicit Unicode code points
    str5 := "\xe6\x97\xa5\xe6\x9c\xac\xe8\xaa\x9e" // the explicit UTF-8 bytes

    println(str1)
    println(str2)
    println(str3)
    println(str4)
    println(str5)
}

output:

日本語
日本語
日本語
日本語
日本語

constant max int

codes:

package main

func main() {
    //2^256=115792089237316195423570985008687907853269984665640564039457584007913129639936
    i := 115792089237316195423570985008687907853269984665640564039457584007913129639936
}

output:

./main.go:6: constant 115792089237316195423570985008687907853269984665640564039457584007913129639936 overflows int

unamed type

codes:

package main

type Student struct {
    name string
    age  int
}

func Display(s struct {
    name string
    age  int
}) {
    println(s.name)
    println(s.age)
}

func main() {
    alice := Student{
        name: "alice",
        age:  16,
    }
    Display(alice)
}

output:

alice
16

Method Sets

codes:

package main

type Str string

func (s Str) Show() {
    println(s)
}

func main() {
    str := Str("Hello World!")
    pstr := &str
    pstr.Show()
}

output:

Hello World!

String Index

codes:

package main

import (
    "fmt"
)

func main() {
    str := "Hello World!"
    fmt.Printf("%c\n", str[6])

    //not allow
    //ptr := &str[6]

    //not allow
    //str[6] = 'w'
}

output:

W

Create Slice from Array

codes:

package main

func main() {
    var array1 [30]int
    for i := 0; i < len(array1); i++ {
        array1[i] = i
    }

    slice1 := array1[10:15]

    println("array's length: ", len(array1))
    println("slice1's length: ", len(slice1))
    println("slice1's capacity: ", cap(slice1))

    for i := 0; i < len(slice1); i++ {
        println(slice1[i])
    }
}

output:

array's length:  30
slice1's length:  5
slice1's capacity:  20
10
11
12
13
14

Create Slice by make

codes:

package main

func main() {
    //not allow
    //slice1 := make([]int)
    //println("slice1， len is ", len(slice1), "capacity is ", cap(slice1))

    slice2 := make([]int, 10)
    println("slice2， len is ", len(slice2), "capacity is ", cap(slice2))

    slice3 := make([]int, 10, 20)
    println("slice3， len is ", len(slice3), "capacity is ", cap(slice3))
}

output:

slice2， len is  10 capacity is  10
slice3， len is  10 capacity is  20