[Yugong series] go teaching course 010 in July 2022 - Boolean and character types of data types

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One 、 Summary of data types

go There are four data types in the language ： The base type , The compound type , Reference type , Interface type .

type	name	length	Zero value	explain
bool	Boolean type	1	false	If its value is not true, it is false , It can't be represented by numbers true or false
byte	Byte type	1	0	uint8 Alias
rune	Character type	4	0	Dedicated to storage unicode code , Equivalent to uint32
int, uint	integer	4 or 8	0	A signed 32 Bit or unsigned 64 position
int8	integer	1	0	-128~ 127,
uint8	integer	1	0	0~ 255
int16	integer	2	0	-32768 ~ 32767,
uint16	integer	2	0	0 ~ 65535
int32	integer	4	0	-2147483648 To 2147483647
uint32	integer	4	0	0 To 4294967295(42 Billion )
int64	integer	8	0	-9223372036854775808 To 9223372036854775807
uint64	integer	8	0	0 To 18446744073709551615 ( 1844 Beijing )
float32	floating-point	4	0.0	Decimal places are accurate to 7 position
float64	floating-point	8	0.0	Decimal places are accurate to 15 position
complex64	Plural type	8
complex128	Plural type	16		64 Bit real number and imaginary number
uintptr	integer	4 or 8		Enough to store pointers uint32 or uint64 Integers
strina	character string		"”	utf-8 character string

Two 、 Boolean type

stay Go In language , With keywords bool To declare Boolean types . Boolean types have only true and false Two values .

package main

import "fmt"

func main() {
    
	var a bool
	a = true
	fmt.Println(a)
	fmt.Printf("%t", a)
}

3、 ... and 、 Character type

Go In language , Each element of a string is called a character , It is mainly divided into the following two types ：

• uint8 type , Or call it byte type , On behalf of ASCII A character of a code .
• rune type , Represents a UTF-8 character . Usually , When you need to deal with Chinese 、 Japanese 、 Korean and other compound characters , Need to use rune type .

package main

import "fmt"

func main()  {
    
	var a byte = 'q'
	fmt.Printf("%d %T\n", a, a) // byte  The actual type of is actually  uint8,  Corresponding  ASCII  Encoded as  113

	var b rune = ' dog '
	fmt.Printf("%d %T\n", b, b) // rune  The actual type of is actually  int32,  Corresponding  Unicode  Encoded as  29356
}