How to add data in golang

Go language is a programming language that has become more popular in recent years. In development, we often need to use data to add this function. So, how to add data in golang? This article will introduce you to the method of adding data in golang in detail.

1. Add elements to the list

In Golang, lists (also called slices) are a very commonly used data type. To add elements to a list, you can use the append() function. This function is a bit like the append() function in Python. For example:

list := []string{"apple", "banana", "orange"}
list = append(list, "pear")
fmt.Println(list)

Execute the above code, the output result is:

[apple banana orange pear]

You can see that after using the append() function, pear is added to the end of the list (string array).

2. Add key-value pairs to dictionary

Dictionary (also called map) is another common data type in Golang. To add key-value pairs to the dictionary, you can use the following syntax:

m := make(map[string]string)
m["name"] = "Tom"
m["age"] = "18"

In the above example, the make() function is used to create an empty dictionary. Then, we can add key-value pairs to the dictionary using the form m["key"] = value. In particular, it is important to note that the keys and values ​​in the dictionary must be of the same data type.

3. Add CSV data

In Golang, you can also add data in CSV (Comma-Separated Values) format. CSV data can be read and written using the encoding/csv package. Here is an example that demonstrates how to write data to a CSV file:

package main

import (
    "encoding/csv"
    "os"
)

func main() {
    file, err := os.Create("data.csv")
    if err != nil {
        panic(err)
    }

    writer := csv.NewWriter(file)
    defer writer.Flush()

    writer.Write([]string{"name", "age", "gender"})
    writer.Write([]string{"Tom", "18", "Male"})
    writer.Write([]string{"Lily", "20", "Female"})
}

In the above code, we first create a file named data.csv. Then, a CSV writer (writer) was created, the writer.Write() method was called, and three rows of data were written in sequence. Finally, we use the defer keyword to ensure that the writer.Flush() method will be executed and the data in the cache will be written to the file before the main() function returns.

4. Add MySQL data

How to add MySQL data in Golang? First, you need to use the database driver in the Go language. There are many ready-made MySQL database drivers in Golang. Here we choose the more popular third-party library-github.com/go-sql-driver/mysql.

We can add MySQL data in Golang according to the following syntax:

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

func main() {
    user := "root"
    password := "root"
    host := "localhost"
    port := "3306"
    database := "test"

    db, err := sql.Open("mysql", user+":"+password+"@tcp("+host+":"+port+")/"+database)
    if err != nil {
        panic(err)
    }

    defer db.Close()

    stmt, err := db.Prepare("INSERT INTO user(name, age, gender) VALUES(?, ?, ?)")
    if err != nil {
        panic(err)
    }

    res, err := stmt.Exec("Tom", 18, "Male")
    if err != nil {
        panic(err)
    }

    lastId, err := res.LastInsertId()
    if err != nil {
        panic(err)
    }

    fmt.Println("LastInsertId:", lastId)
}

In the above code, we first connect to the MySQL database through the sql.Open() function. Next, use the Prepare() method to preprocess the SQL statement. When executing the SQL statement, we can use the Exec() function to perform operations such as INSERT, UPDATE, and DELETE.

Finally, use the LastInsertId() method to get the ID of the record just inserted to ensure that we have successfully added data to the database.

Summary

This article introduces several methods of adding data in Golang, including adding elements to lists, adding key-value pairs to dictionaries, adding CSV data, and adding MySQL data. Of course, you can also use other methods to implement the data addition function, and the specific effect will depend on the actual situation. In short, Golang is a very flexible and efficient programming language that is widely used in daily development. I hope this article will be helpful to you.

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