golang replacement writing

In Golang, replacing and writing files are relatively common operations. Replacement can be used to modify the text in the file, and writing can be used to add new content to the file.

Replace text in a file

In Golang, we can use the ReplaceAll function to replace text in a file. The syntax of this function is as follows:

ReplaceAll(s, old, new string) string

where s represents the string to be replaced, old represents the string to be replaced, new Indicates the string to be replaced. The following is an example:

package main

import (
    "fmt"
    "io/ioutil"
    "strings"
)

func main() {
    // 读取文件内容
    data, err := ioutil.ReadFile("test.txt")
    if err != nil {
        fmt.Println("Read file error:", err)
        return
    }

    // 将文件内容转换成字符串
    content := string(data)

    // 替换文本内容
    newContent := strings.ReplaceAll(content, "Go语言", "Golang")

    // 将替换后的内容写回原文件
    err = ioutil.WriteFile("test.txt", []byte(newContent), 0666)
    if err != nil {
        fmt.Println("Write file error:", err)
        return
    }

    fmt.Println("Replace file content success.")
}

The above code first reads the contents of the test.txt file, and then uses the ReplaceAll function to replace the Go language# in the file. ## is replaced with Golang. Finally, the replaced content is written back to the original file.

WriteFile function. The syntax of this function is as follows:

WriteFile(filename string, data []byte, perm os.FileMode) error

filename represents the file name, data represents the content to be written to the file, and perm represents the file permissions . The following is an example:

package main

import (
    "fmt"
    "os"
)

func main() {
    // 打开文件
    file, err := os.OpenFile("test.txt", os.O_APPEND|os.O_WRONLY, 0666)
    if err != nil {
        fmt.Println("Open file error:", err)
        return
    }
    defer file.Close()

    // 写入文件
    _, err = file.WriteString("Hello, Golang.")
    if err != nil {
        fmt.Println("Write file error:", err)
        return
    }

    fmt.Println("Write file success.")
}

test.txt file and uses the os.O_APPEND|os.O_WRONLY mode to open it in write-only mode. , if the file does not exist, create it. Then use the WriteString function to write the string Hello, Golang. to the file. Finally close the file.

ReplaceAll function and the WriteFile function. At the same time, you need to pay attention to the file opening mode and file permissions, as well as error handling.

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