Five must-learn libraries to help you learn Go language

Five must-learn libraries to help you learn the Go language

As a simple and efficient programming language, the Go language is becoming more and more popular among developers. In order to better learn and apply the Go language, it is essential to master some commonly used class libraries. This article will introduce the five must-learn class libraries, which are:

1. fmt: The fmt class library is the standard for formatting input and output in the Go language. Library. Through this class library, various formatted outputs can be realized, such as printing variables, formatting strings, etc. The following is a simple example:

package main

import "fmt"

func main() {
    var num1 = 10
    var num2 = 20
    var sum = num1 + num2

    fmt.Printf("num1: %d, num2: %d, sum: %d
", num1, num2, sum)
}

2. net/http: The net/http class library is used in the Go language to handle HTTP requests. and responsive standard libraries. Through this class library, you can easily create HTTP servers and clients. The following is an example of a simple HTTP server:

package main

import (
    "fmt"
    "net/http"
)

func handler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "Hello, World!")
}

func main() {
    http.HandleFunc("/", handler)
    http.ListenAndServe(":8080", nil)
}

3. database/sql：database/sql class library is used in Go language Standard library for connecting to and manipulating databases. Through this class library, you can easily connect to various types of databases and execute SQL statements. The following is a simple example of connecting to a MySQL database and querying data:

package main

import (
    "database/sql"
    "fmt"
    _ "github.com/go-sql-driver/mysql"
)

func main() {
    db, err := sql.Open("mysql", "user:password@tcp(127.0.0.1:3306)/database")
    if err != nil {
        panic(err.Error())
    }
    defer db.Close()

    rows, err := db.Query("SELECT * FROM table")
    if err != nil {
        panic(err.Error())
    }

    defer rows.Close()

    for rows.Next() {
        var id int
        var name string
        err = rows.Scan(&id, &name)
        if err != nil {
            panic(err.Error())
        }

        fmt.Println("ID:", id, "Name:", name)
    }
}

4. encoding/json：encoding/json The class library is Go The standard library in the language for processing JSON data. Through this class library, you can convert Go data structures into JSON strings, or parse JSON strings into Go data structures. The following is a simple example:

package main

import (
    "encoding/json"
    "fmt"
)

type Person struct {
    Name string `json:"name"`
    Age  int    `json:"age"`
}

func main() {
    person := Person{Name: "Alice", Age: 30}
    jsonBytes, err := json.Marshal(person)
    if err != nil {
        panic(err.Error())
    }

    fmt.Println(string(jsonBytes))

    var newPerson Person
    err = json.Unmarshal(jsonBytes, &newPerson)
    if err != nil {
        panic(err.Error())
    }

    fmt.Println(newPerson)
}

5. time: The time class library is the standard library for processing time and date in the Go language . Through this class library, you can obtain the current time, calculate time difference, format time and other operations. The following is a simple example:

package main

import (
    "fmt"
    "time"
)

func main() {
    currentTime := time.Now()
    fmt.Println("Current time:", currentTime)

    futureTime := currentTime.AddDate(0, 0, 7)
    fmt.Println("Future time (7 days later):", futureTime)

    layout := "2006-01-02 15:04:05"
    timeStr := currentTime.Format(layout)
    fmt.Println("Formatted time:", timeStr)
}

By studying the above five must-learn class libraries, I believe that I can better understand and apply the Go language. I hope it will be helpful to everyone on the road to learning the Go language.

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