go基础学习day4

bool类型

package main

import (
    "fmt"
)

func main() {
    /* var a bool = true
    var b = false
    c := true
    fmt.Printf("a: %v\n", a)
    fmt.Printf("b: %v\n", b)
    fmt.Printf("c: %v\n", c) */

    //在判断中
    /* age := 18
    if age >= 18 {
        fmt.Println("成年")
    } else {
        fmt.Println("未成年")
    } */

    /*  age := 16
        b := age >= 18
        fmt.Printf("b: %v\n", b)    //输出false
        if b {
            fmt.Println("成年")
        } else {
            fmt.Println("未成年")
        } */

    /* count := 10
    for i := 0; i < count; i++ {
        fmt.Printf("i=%v\n", i)
    } */

    age, gender := 18, "男"
    if age >= 18 && gender == "男" {
        fmt.Println("成年男")
    }
}

数字类型

有符号int8

无符号uint8

十进制：输出时用%d

二进制：输出时用%b

八进制：定义数字时用0开头，输出%x

十六进制：定义数字时用0x开头，输出时用%X

浮点数：输出用%f

import (
    "fmt"
    "math"
    "unsafe"
)

func main() {
    var i8 int8
    fmt.Println("%T,%dB %v~%v", i8, math.MinInt8)
}

字符串

package main

import (
    "fmt"
    "strings"
)

func main() {
    /*  s1 := "hello"
        s2 := `
        ni
        hao
        a
        `
        // s3 := s1 + s2
        s3 := strings.Join([]string{s1, s2}, ",")
        fmt.Printf("s1: %v\n", s1)
        fmt.Printf("s2: %v\n", s2)
        fmt.Printf("s3: %v\n", s3) */

    /* 转义字符
    \n  回车
    \t  tab键
    \\  转义\ */

    //切片
    s := "hello world"
    fmt.Printf("s[1]: %c\n", s[1])
    fmt.Printf("s[4:]: %v\n", s[4:])

    //字符串长度
    fmt.Printf("len(s): %v\n", len(s))
    //转换为数组
    s1 := strings.Split(s, "")
    fmt.Printf("s1: %v\n", s1)
    //是否包含
    fmt.Printf("strings.Contains(s, \"hello\"): %v\n", strings.Contains(s, "hello"))
}