Golang : Interpolating or substituting variables in string examples
For this quick tutorial, we will explore how to interpolate(substitute) actual data into variables inside a string. Will keep these examples as simple as possible and once you are comfortable, do explore the advanced example at https://www.socketloop.com/tutorials/golang-auto-generate-reply-email-with-text-template-package
Example 1:
package main
import (
"fmt"
)
func main() {
msg := "%s has %d messages."
name := "Steve"
num := 50
result := fmt.Sprintf(msg, name, num)
fmt.Println(result)
}
Output:
Steve has 50 messages.
To substitute more variables ( higher than 3), it is recommended to use the text/template
package.
Example 2:
package main
import (
"fmt"
"os"
"text/template"
)
type Data struct {
Name string // has to be uppercase/exportable/public
Num uint // for the interpolation/substitution to work
}
func main() {
msg := "{{.Name}} has {{.Num}} messages.\n"
substitute := Data{"Steve", 50}
tmpl, err := template.New("msg").Parse(msg)
err = tmpl.Execute(os.Stdout, substitute)
if err != nil {
fmt.Println(err)
}
}
Output:
Steve has 50 messages.
References:
https://www.socketloop.com/tutorials/golang-auto-generate-reply-email-with-text-template-package
https://golang.org/pkg/text/template/
https://www.socketloop.com/tutorials/golang-find-replace-character-in-string
See also : Golang : Auto-generate reply email with text/template package
By Adam Ng
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