Best practices for Go language file operations

Best practices for Go language file operations: use os.Open/os.OpenFile to open the file and automatically close it (defer file.Close()); use ioutil.ReadAll to read the entire file or bufio.NewReader to buffer and read large files ;Use os.Create/os.OpenFile to open the file in write mode, use ioutil.WriteFile to write content once or file.Write to write step by step; use os.OpenFile to append to the file in append mode, use file.Seek to locate to the end and Use file.Write to append content; use os.Stat to check whether the file exists (if it does not exist, return os.ErrNotExist); use os.Remove to delete the file (if it does not exist, return os.ErrNotExist).

Go language file operation best practices

File operation in Go is a common task, understand the best practices Crucial to improve efficiency and write robust code.

Open the file

• Use the os.Open or os.OpenFile function to open the file, specify reading and writing model.
• Use defer file.Close() to automatically close the file, even if an error occurs.

file, err := os.Open("filename.txt")
if err != nil {
    // 处理错误
}
defer file.Close()

Read file

• Use ioutil.ReadAll to read the entire file content into byte slices.
• Use bufio.NewReader to create a buffered reader for efficient reading of large files.

data, err := ioutil.ReadAll(file)
if err != nil {
    // 处理错误
}

Write to file

• Use os.Create or os.OpenFile to write mode to open the file.
• Use ioutil.WriteFile to write the entire content to the file at once.
• Use file.Write to write content step by step.

newFile, err := os.Create("newfilename.txt")
if err != nil {
    // 处理错误
}
defer newFile.Close()

_, err = newFile.Write([]byte("文件内容"))
if err != nil {
    // 处理错误
}

Append to file

• Open the file in append mode using os.OpenFile.
• Use file.Seek(0, 2) to locate the end of the file.
• Use file.Write to append content.

file, err := os.OpenFile("filename.txt", os.O_APPEND|os.O_WRONLY, 0666)
if err != nil {
    // 处理错误
}
defer file.Close()

_, err = file.Seek(0, 2)
if err != nil {
    // 处理错误
}

_, err = file.Write([]byte("追加内容"))
if err != nil {
    // 处理错误
}

Check if the file exists

• Use os.Stat to check if the file exists. If the file does not exist, then Returns os.ErrNotExist error.

if _, err := os.Stat("filename.txt"); os.IsNotExist(err) {
    // 文件不存在
}

Delete the file

• Use os.Remove to delete the file, if the file does not exist, return os.ErrNotExist Error.

err := os.Remove("filename.txt")
if err != nil {
    // 处理错误
}

Practical case

Suppose we need to move the data in the file from one location to another:

package main

import (
    "fmt"
    "io/ioutil"
    "log"
    "os"
)

func main() {
    // 打开源文件
    srcFile, err := os.Open("source.txt")
    if err != nil {
        log.Fatal(err)
    }
    defer srcFile.Close()

    // 读取源文件的内容
    srcData, err := ioutil.ReadAll(srcFile)
    if err != nil {
        log.Fatal(err)
    }

    // 关闭源文件
    srcFile.Close()

    // 打开目标文件
    dstFile, err := os.Create("destination.txt")
    if err != nil {
        log.Fatal(err)
    }
    defer dstFile.Close()

    // 写入目标文件
    if _, err = dstFile.Write(srcData); err != nil {
        log.Fatal(err)
    }

    // 关闭目标文件
    dstFile.Close()

    fmt.Println("文件已移动成功")
}

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