golang template if

package main

import (
    "os"
    "text/template"
)

func main() {
    const tmpl = `{{if .}}Not empty{{else}}Empty{{end}}`
    t := template.Must(template.New("tmpl").Parse(tmpl))
    data := []int{1, 2, 3}

    if err := t.Execute(os.Stdout, data); err != nil {
        panic(err)
    }
}

Explanation: 1. package main: Specifies that this Go file belongs to the main package, which is the entry point for the executable program.

1. import: Imports necessary packages. os is used for operating system functionality, and text/template provides support for text templates.

2. func main() { ... }: Defines the main function, which is the entry point of the program.

3. const tmpl ={{if .}}Not empty{{else}}Empty{{end}}`: Defines a constanttmplcontaining a text template. The template uses the{{if}}conditional action to check if the provided data (denoted by.`) is not empty. If it's not empty, it will print "Not empty"; otherwise, it will print "Empty".

4. t := template.Must(template.New("tmpl").Parse(tmpl)): Creates a new template named "tmpl" using template.New("tmpl"). The Parse function parses the template defined earlier and returns a pointer to a Template struct. template.Must is used to handle any parsing errors by panicking if an error occurs.

5. data := []int{1, 2, 3}: Initializes a slice named data containing integers 1, 2, and 3.

6. if err := t.Execute(os.Stdout, data); err != nil { panic(err) }: Executes the template t by applying it to the data slice. If any error occurs during execution, it will be caught and the program will panic, halting its execution.

This program demonstrates the use of the if conditional action within a Go template to check if the provided data is empty or not, and then prints the corresponding message based on that condition.