如何将切片转换为数组? [英] How do you convert a slice into an array?

问题描述

我正在尝试编写一个读取RPM文件的应用程序.每个块的开头都有一个 [4] byte 的Magic char.

I am trying to write an application that reads RPM files. The start of each block has a Magic char of [4]byte.

这是我的结构

type Lead struct {
  Magic        [4]byte
  Major, Minor byte
  Type         uint16
  Arch         uint16
  Name         string
  OS           uint16
  SigType      uint16
}

我正在尝试执行以下操作:

I am trying to do the following:

lead := Lead{}
lead.Magic = buffer[0:4]

我正在在线搜索，不确定如何从切片到数组(不进行复制).我总是可以将Magic设置为 [] byte (甚至是 uint64 )，但是我对如何从 [] byte 到 [4] byte (如果需要)?

I am searching online and not sure how to go from a slice to an array (without copying). I can always make the Magic []byte (or even uint64), but I was more curious on how would I go from type []byte to [4]byte if needed to?

推荐答案

内置方法 copy 只会将切片复制到切片，而不是将切片复制到数组.

The built in method copy will only copy a slice to a slice NOT a slice to an array.

您必须欺骗 copy 认为数组是一个切片

You must trick copy into thinking the array is a slice

copy(varLead.Magic[:], someSlice[0:4])

或使用for循环进行复制:

Or use a for loop to do the copy:

for index, b := range someSlice {

    varLead.Magic[index] = b

}

或者像zupa使用文字所做的那样做.我已经添加到他们的工作示例中.

Or do as zupa has done using literals. I have added onto their working example.

去游乐场

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