How to convert a string to lowercase in Go

The strings package is a Go standard library package that contains functions to manipulate UTF-8 encoded strings.

The ToLower() method

It provides the ToLower() method, which can convert a string to a lower case.

Returns

This returns a copy of the string input where all the Unicode characters are mapped to its lowercase variant.

Syntax


func ToLower(s string) string

Arguments

  • This method takes a string s as input.

  • It returns a string which is the lowercase of the input string.

Code

First, we imported the fmt and strings package to our program in the code below:

package main
import (
"fmt"
"strings"
)
func main() {
str1 := "NewYork"
str2 := "CITY OF DREAMS"
fmt.Println("Initial Strings")
fmt.Println(str1);
fmt.Println(str2);
fmt.Println("\nAfter Calling ToLower()")
fmt.Println(strings.ToLower(str1))
fmt.Println(strings.ToLower(str2))
}

Explanation

After importing fmt we call the ToLower() method with New York as the input string. This returns new york as it returns a new string after converting it to lowercase.

We then call the ToLower() method with CITY OF DREAMS as the input string. This returns city of dreams after converting the input to lowercase.

We show the output of all these operations using the Println() method of the fmt package.

Output

The program prints below output and exits:

Initial Strings
NewYork
CITY OF DREAMS

After Calling ToLower()
newyork
city of dreams

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