Use the fmt.Fprint function to write formatted data to the specified io.Writer

Use the fmt.Fprint function to write formatted data to the specified io.Writer

In the Go language, the fmt package is a standard package for formatted input and output, and the Fprint function can The formatted data is written to the specified io.Writer. This article will introduce how to use this function for output operations.

First, we need to import the fmt and os packages. fmt is used for formatted output, os is used for operating files and reading and writing IO.

import (
    "fmt"
    "os"
)

After that, we need to obtain an io.Writer instance, which can be a file, standard output stream (os.Stdout) or network connection, etc. In this article, we use writing to a file as an example.

First, we need to create a file and open it:

file, err := os.Create("output.txt") // 创建一个名为output.txt的文件
if err != nil {
    panic(err)
}
defer file.Close() // 在函数结束前关闭文件

Next, we can use the fmt.Fprint function to write data to the file. The first parameter of this function is an io.Writer instance, which is used to specify the output target. In this example, we pass in file as the first parameter.

data := "Hello, World!"
fmt.Fprint(file, data)

In this way, we write the data "Hello, World!" into the output.txt file.

The complete code is as follows:

package main

import (
    "fmt"
    "os"
)

func main() {
    file, err := os.Create("output.txt") // 创建一个名为output.txt的文件
    if err != nil {
        panic(err)
    }
    defer file.Close()

    data := "Hello, World!"
    fmt.Fprint(file, data)
}

After executing the above code, a file named output.txt will be generated in the directory where the program is located, and "Hello, World" will be written in it. !".

It should be noted that when using the fmt.Fprint function, the first parameter must be an instance that implements the io.Writer interface. In addition to file io, you can also use os.Stdout as a parameter to output the content to the console.

data := "Hello, World!"
fmt.Fprint(os.Stdout, data) // 输出到控制台

The above code will print "Hello, World!" on the console.

Summary: By using the fmt.Fprint function, we can easily write formatted data to the specified io.Writer. This is useful for outputting to a file, a network connection, or the standard output stream. When using this function, we need to first obtain an instance that implements the io.Writer interface and pass it in as the first parameter.

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