In-depth research and analysis of Golang function library

The Go function library provides a rich set of built-in functions, including: fmt: used for formatting and printing data; io: used for input/output operations; math: provides mathematical functions and constants; net: used for network connections and Server functions; os: used to interact with the operating system; regexp: provides regular expression support. A deep understanding of these libraries can improve the development capabilities of Go developers.

In-depth exploration and analysis of Go function library

Introduction:
Go function library provides It has a rich set of built-in functions to simplify the coding process for developers. This article will take an in-depth look at several commonly used Go function libraries, focusing on their uses and practical application scenarios.

fmt package

• #Purpose: Used to format and print data.
• Actual combat:

package main

import "fmt"

func main() {
    fmt.Printf("Name: %s, Age: %d\n", "John Doe", 30)
}

io package

• Usage: provided Input/output operations on files, pipes, and network connections.
• Practical combat: The following code reads data from a file:

package main

import (
    "fmt"
    "io"
    "os"
)

func main() {
    f, err := os.Open("data.txt")
    if err != nil {
        fmt.Println(err)
        return
    }
    defer f.Close()

    data := make([]byte, 1024)
    n, err := f.Read(data)
    if err != nil {
        fmt.Println(err)
        return
    }

    fmt.Println(string(data[:n]))
}

math package

• Purpose: Provides mathematical functions and constants.
• Practical combat: The following code finds the maximum value of two numbers:

package main

import "fmt"
import "math"

func main() {
    fmt.Println(math.Max(10, 20))
}

net package

• Purpose:Provide network connection and server functions.
• Practical combat: The following code creates an HTTP server:

package main

import (
    "fmt"
    "net/http"
)

func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, "Hello, World!")
    })
    http.ListenAndServe(":8080", nil)
}

os package

• Purpose: Interacts with the operating system and provides functions for operating files, processes, time, etc.
• Practical combat: The following code obtains the absolute path of the current directory:

package main

import (
    "fmt"
    "os"
)

func main() {
    dir, err := os.Getwd()
    if err != nil {
        fmt.Println(err)
        return
    }
    fmt.Println(dir)
}

regexp package

• Purpose: Provide regular expression support.
• Practice: The following code matches numbers in the input string:

package main

import (
    "fmt"
    "regexp"
)

func main() {
    str := "This is a string with numbers: 123, 456, 789"
    r, err := regexp.Compile("[0-9]+")
    if err != nil {
        fmt.Println(err)
        return
    }
    matches := r.FindAllString(str, -1)
    fmt.Println(matches)
}

By exploring these commonly used Go function libraries, developers can better understand Its uses and application scenarios, thereby improving their Go development capabilities.

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