Golang 按行读取文件的三种方法小结

func (s *Scanner) Scan() bool

// ReadLines reads all lines of the file.
func ReadLines(path string) ([]string, error) {
    file, err := os.Open(path)
    if err != nil {
        return nil, err
    }
    defer file.Close()

    var lines []string
    scanner := bufio.NewScanner(file)
    for scanner.Scan() {
        lines = append(lines, scanner.Text())
    }
    return lines, scanner.Err()
}

// ReadLinesV2 reads all lines of the file.
func ReadLinesV2(path string) ([]string, error) {
    file, err := os.Open(path)
    if err != nil {
        return nil, err
    }
    defer file.Close()

    var lines []string
    reader := bufio.NewReader(file)
    for {
        // ReadString reads until the first occurrence of delim in the input,
        // returning a string containing the data up to and including the delimiter.
        line, err := reader.ReadString('\n')
        if err == io.EOF {
            lines = append(lines, line)
            break
        }
        if err != nil {
            return lines, err
        }
        lines = append(lines, line[:len(line)-1])
    }
    return lines, nil
}

// ReadLinesV3 reads all lines of the file.
func ReadLinesV3(path string) ([]string, error) {
    f, err := os.Open(path)
    if err != nil {
        return nil, err
    }
    defer f.Close()

    var lines []string
    r := bufio.NewReader(f)
    for {
        // ReadLine is a low-level line-reading primitive.
        // Most callers should use ReadBytes('\n') or ReadString('\n') instead or use a Scanner.
        bytes, _, err := r.ReadLine()
        if err == io.EOF {
            break
        }
        if err != nil {
            return lines, err
        }
        lines = append(lines, string(bytes))
    }
    return lines, nil
}

package main

import (
    "github.com/dablelv/go-huge-util/file"
)

func main() {
    path := "your/file/path"
    lines, err := file.ReadLines(path)
    lines, err = file.ReadLinesV2(path)
    lines, err = file.ReadLinesV3(path)
}