HasPrefix, HasSuffix

Most languages (including Go) provide helpful methods to test the starts and ends of strings. This avoids the need for complex loops.

In Go, we have HasPrefix and HasSuffix. These are string "starts with" and "ends with" methods. We can test 1 char or more at the beginning or ending parts of a string.

HasPrefix example

This func returns true or false. It receives two arguments: the first is the string we are trying to test. The second is a possible "prefix" of that string.

package main

import (
    "fmt"
    "strings"
)

func main() {
    prefix := "New "
    city := "New York"

    // See if city string begins with prefix string.
    if strings.HasPrefix(city, prefix) {
        fmt.Println(true)
    }
}
true

HasSuffix

This tests the end chars of a string. We can test the last character with a 1-char string—for example, we can test to see if we have a question.

package main

import (
    "fmt"
    "strings"
)

func main() {
    value := "Is there a box?"

    // See if we have a question.
    if strings.HasSuffix(value, "?") {
        fmt.Println("ENDS WITH QUESTION")
    }
}
ENDS WITH QUESTION

A review

Methods like HasPrefix and HasSuffix are not hard to use. But simple examples can make them easier to understand at first. They are useful in many Go programs.