Similar to this question, what is the idiomatic way to process a file one byte at a time in go?
Put another way, is there a better way to write the following?
file, err := ioutil.ReadFile(filename)
file_string = string(file)
for i, c := range file_string {
// -snip-
}
You're reading the entire file as a string (not bytes) at once, then processing it rune-by-rune (not byte-by-byte). To literally read the file one byte at a time (which is very likely not what you want), you must do exactly that:
f, err := os.Open("path")
if err != nil {
panic(err)
}
b := make([]byte, 1)
for {
err := f.Read(b)
if err != nil && !errors.Is(err, io.EOF) {
fmt.Println(err)
break
}
// process the one byte b[0]
if err != nil {
// end of file
break
}
}
However, what you more likely want is to read the file efficiently, and process it one byte at a time. For this, you should use a buffered reader:
f, err := os.Open("path")
if err != nil {
panic(err)
}
br := bufio.NewReader(f)
// infinite loop
for {
b,err := br.ReadByte()
if err != nil && !errors.Is(err, io.EOF) {
fmt.Println(err)
break
}
// process the one byte b
if err != nil {
// end of file
break
}
}
