如何将单个字符转换为单个字节？

Question

I am trying to check if a given character is present in a byte:

//readBuf: []byte
//n: int
for i:=0;i<n;i++{
    if readBuf[i]=="?"{
        return true
    }
}

"?" is of type string, so I am getting an error, since readBuf[i] is a byte. How can I convert "?" to a byte to be able to compare it to readBuf[i]?

It seems that []byte("?")[0] is working (convert the 1-element string to 1-element byte array, the extract the first value), but I am sure this is not the correct way of doing it.

Answer 1

The rune literal '?' is the untyped integer value of the question mark rune.

Use bytes.ContainsRune:

if bytes.ContainsRune(readBuf[:n], '?') {
   return true
}

Because the character ? is encoded as a single byte in UTF-8, the test can also be written as:

for _, b := range readBuf[:n] {
    if b =='?'{   
        return true
    }
}