开始-执行无符号移位操作

Question

Is there anyway to perform an unsigned shift (namely, unsigned right shift) operation in Go? Something like this in Java

0xFF >>> 3

The only thing I could find on this matter is this post but I'm not sure what I have to do.

Thanks in advance.

Answer 1

The Go Programming Language Specification

Numeric types

A numeric type represents sets of integer or floating-point values. The predeclared architecture-independent numeric types include:

uint8       the set of all unsigned  8-bit integers (0 to 255)
uint16      the set of all unsigned 16-bit integers (0 to 65535)
uint32      the set of all unsigned 32-bit integers (0 to 4294967295)
uint64      the set of all unsigned 64-bit integers (0 to 18446744073709551615)

int8        the set of all signed  8-bit integers (-128 to 127)
int16       the set of all signed 16-bit integers (-32768 to 32767)
int32       the set of all signed 32-bit integers (-2147483648 to 2147483647)
int64       the set of all signed 64-bit integers (-9223372036854775808 to 9223372036854775807)

byte        alias for uint8
rune        alias for int32

The value of an n-bit integer is n bits wide and represented using two's complement arithmetic.

There is also a set of predeclared numeric types with implementation-specific sizes:

uint     either 32 or 64 bits
int      same size as uint
uintptr  an unsigned integer large enough to store the uninterpreted bits of a pointer value

Conversions are required when different numeric types are mixed in an expression or assignment.

Arithmetic operators

<<   left shift             integer << unsigned integer
>>   right shift            integer >> unsigned integer

The shift operators shift the left operand by the shift count specified by the right operand. They implement arithmetic shifts if the left operand is a signed integer and logical shifts if it is an unsigned integer. There is no upper limit on the shift count. Shifts behave as if the left operand is shifted n times by 1 for a shift count of n. As a result, x << 1 is the same as x*2 and x >> 1 is the same as x/2 but truncated towards negative infinity.

In Go, it's an unsigned integer shift. Go has signed and unsigned integers.

It depends on what type the value 0xFF is. Assume it's one of the unsigned integer types, for example, uint.

package main

import "fmt"

func main() {
    n := uint(0xFF)
    fmt.Printf("%X
", n)
    n = n >> 3
    fmt.Printf("%X
", n)
}

Output:

FF
1F

Assume it's one of the signed integer types, for example, int.

package main

import "fmt"

func main() {
    n := int(0xFF)
    fmt.Printf("%X
", n)
    n = int(uint(n) >> 3)
    fmt.Printf("%X
", n)
}

Output:

FF
1F