本文翻译自：
reading file line by line in go
I’m unable to find
file.ReadLine
function in Go.
我在Go中找不到
file.ReadLine
函数。
I can figure out how to quickly write one, but just wondering if I’m overlooking something here.
我可以弄清楚如何快速编写一个，但是想知道我是否在这里忽略了一些东西。
How does one read a file line by line?
如何逐行读取文件？
#1楼
参考：
https://stackoom.com/question/AKcd/逐行读取文件
#2楼
EDIT: As of go1.1, the idiomatic solution is to use
bufio.Scanner
编辑：从go1.1开始，惯用的解决方案是使用
bufio.Scanner
I wrote up a way to easily read each line from a file.
我写了一种轻松读取文件中每一行的方法。
The Readln(*bufio.Reader) function returns a line (sans \\n) from the underlying bufio.Reader struct.
Readln（* bufio.Reader）函数从基础bufio.Reader结构返回一行（sans \\ n）。
// Readln returns a single line (without the ending \n)
// from the input buffered reader.
// An error is returned iff there is an error with the
// buffered reader.
func Readln(r *bufio.Reader) (string, error) {
var (isPrefix bool = true
err error = nil
line, ln []byte
)
for isPrefix && err == nil {
line, isPrefix, err = r.ReadLine()
ln = append(ln, line...)
}
return string(ln),err
}
You can use Readln to read every line from a file.
您可以使用Readln读取文件中的每一行。
The following code reads every line in a file and outputs each line to stdout.
以下代码读取文件中的每一行，并将每一行输出到stdout。
f, err := os.Open(fi)
if err != nil {
fmt.Printf("error opening file: %v\n",err)
os.Exit(1)
}
r := bufio.NewReader(f)
s, e := Readln(r)
for e == nil {
fmt.Println(s)
s,e = Readln(r)
}
Cheers!
干杯!
#3楼
bufio.Reader.ReadLine()
works well.
bufio.Reader.ReadLine（）
运作良好。
But if you want to read each line by a string, try to use
ReadString(‘\\n’)
.
但是，如果
要按
字符串读取每一行，请尝试使用
ReadString（’\\ n’）
。
It doesn’t need to reinvent the wheel.
不需要重新发明轮子。
#4楼
You can also use ReadString with \\n as a separator:
您还可以使用带有\\ n的ReadString作为分隔符：
f, err := os.Open(filename)
if err != nil {
fmt.Println("error opening file ", err)
os.Exit(1)
}
defer f.Close()
r := bufio.NewReader(f)
for {
path, err := r.ReadString(10) // 0x0A separator = newline
if err == io.EOF {
// do something here
break
} else if err != nil {
return err // if you return error
}
}
#5楼
// strip '\n' or read until EOF, return error if read error
func readline(reader io.Reader) (line []byte, err error) {
line = make([]byte, 0, 100)
for {
b := make([]byte, 1)
n, er := reader.Read(b)
if n > 0 {
c := b[0]
if c == '\n' { // end of line
break
}
line = append(line, c)
}
if er != nil {
err = er
return
}
}
return
}
#6楼
In Go 1.1 and newer the most simple way to do this is with a
bufio.Scanner
.
在Go 1.1和更高版本中，最简单的方法是使用
bufio.Scanner
。
Here is a simple example that reads lines from a file:
这是一个从文件读取行的简单示例：
package main
import (
"bufio"
"fmt"
"log"
"os"
)
func main() {
file, err := os.Open("/path/to/file.txt")
if err != nil {
log.Fatal(err)
}
defer file.Close()
scanner := bufio.NewScanner(file)
for scanner.Scan() {
fmt.Println(scanner.Text())
}
if err := scanner.Err(); err != nil {
log.Fatal(err)
}
}
This is the cleanest way to read from a
Reader
line by line.
这是逐行从
Reader
读取的最干净的方法。
There is one caveat: Scanner does not deal well with lines longer than 65536 characters.
请注意以下几点：扫描程序不能处理超过65536个字符的行。
If that is an issue for you then then you should probably roll your own on top of
Reader.Read()
.
如果这对您来说是个问题，那么您可能应该将自己的代码放在
Reader.Read()
之上。