如何改善此文件的读取代码

Question

I currently have this piece of code that will read a file line by line (delimited by a )

file, _ := os.Open(filename) //deal with the error later
defer file.Close()

buf := bufio.NewReader(file)
for line, err := buf.ReadString('
'); err != io.EOF; line, err = buf.ReadString('
')
{
    fmt.Println(strings.TrimRight(line, "
"))
}

However I don't feel comfortable with writing buf.ReadString(" ") twice in the for loop, does anyone have any suggestions for improvement?

Answer 1

bufio.ReadString reads until the first occurrence of delim in the input, returning a string containing the data up to and including the delimiter. If ReadString encounters an error before finding a delimiter, it returns the data read before the error and the error itself (often io.EOF). ReadString returns err != nil if and only if the returned data does not end in delim.

If buf.ReadString(' ') returns an error other than io.EOF, for example bufio.ErrBufferFull, you will be in an infinite loop. Also, if the file doesn't end in a ' ', you silently ignore the data after the last ' '.

Here's a more robust solution, which executes buf.ReadString(' ') once.

package main

import (
    "bufio"
    "fmt"
    "io"
    "os"
    "strings"
)

func main() {
    filename := "FileName"
    file, err := os.Open(filename)
    if err != nil {
        fmt.Println(err)
        return
    }
    defer file.Close()
    buf := bufio.NewReader(file)
    for {
        line, err := buf.ReadString('
')
        if err != nil {
            if err != io.EOF || len(line) > 0 {
                fmt.Println(err)
                return
            }
            break
        }
        fmt.Println(strings.TrimRight(line, "
"))
    }
}