Golang String Starts with

In go, a string is defined as a slice of bytes. We can also define strings as a sequence of variable-width characters where each character is represented by one or more bytes. In Go, strings are immutable and occupy less memory as Go uses the UTF-8 standard.

With strings being one of the basic types, learning how to perform various operations becomes essential.

In this guide, you will learn how to check if a string begins with a specified substring or prefix or not.

Strings. HasPrefix()

To check if a string begins with a specific substring, we will use the HasPrefix() method from the strings package.

You will need to import the strings package, as shown in the example import clause below:

import "strings"

Once imported, you can use the methods from the package.

The syntax for the HasPrefix() method is as shown:

func HasPrefix(str, substring) bool

The function takes the string and the substring to check as the parameters. The function returns a Boolean true if the string begins with the specified substring. Otherwise, the function returns a Boolean false.

To better understand how the function works, consider the example below:

package main
import (
"fmt"
"strings"
)

func main() {
str_1 := "Hello everyone and welcome to Linuxhint"
str_2 := "Here, you can learn everything tech related."
my_prefix := " "
// check if string starts with a specified prefix
fmt.Println(strings.HasPrefix(str_1, "Hello"))
fmt.Println(strings.HasPrefix(str_2, "Hello"))
fmt.Println(strings.HasPrefix(str_2, "Here"))
fmt.Println(strings.HasPrefix(str_1, "Linuxhint"))
fmt.Println(strings.HasPrefix(str_2, my_prefix))
fmt.Println(strings.HasPrefix(str_1, " "))
}

The example above tests if the strings start with a specified prefix. As you will see, you can specify the prefix value as a string literal or as a variable.

The resulting output is as shown:

true
false
true
false
false
false

Closing

This guide shows you how to use the strings. HasPrefix() method checks if a string starts with a specified substring.

Thanks for reading!

Golang String Starts with

Strings. HasPrefix()

Closing

About the author

John Otieno