How To Compare Strings in Golang

In this blog, we will learn how to compare strings in Golang.

First we will learn simple string comparison in Golang using relational operator  i.e, ==, !=, >=, <=, <, >.

Compare String using Relational Operators

fmt.Println("abc == abc :", "abc" == "abc")
fmt.Println("abc == ABC :", "abc" == "ABC")
fmt.Println("abc == def :", "abc" < "def")
fmt.Println("abc == def :", "abc" > "def")

abc == abc : true
abc == ABC : false
abc == def : false
def == abc : false

String Comparision in Golang using the relational operators is case-sensitive.

Let’s see another way of comparing strings i.e compare function in the strings package.

Golang String Comparison using Compare Function

The Golang String Package has a Compare function which returns an integer comparing two strings lexicographically.

func Compare(s, t string) int

Compare Function	Return Value
string1 == string2	0
string1 < string2	-1
string1 > string2	+1

fmt.Println(strings.Compare("abc", "abc"))
fmt.Println(strings.Compare("bca", "cba"))
fmt.Println(strings.Compare("bca", "abc"))

Output:

0
-1
1

The Compare function is also case-sensitive.

Example:

fmt.Println(strings.Compare("a", "a"))
fmt.Println(strings.Compare("A", "a"))
fmt.Println(strings.Compare("a", "A"))

Output:

0
-1
1

Golang Strings Package Compare function compares according to the ASCII value.

A-Z has ASCII value of 65-90 while a-z has ASCII value of 97-122, and by this a > A and thus the compare function returns +1.

The above two string comparison ways discussed above were case-sensitive, let’s now see a case-insensitive way to compare strings.

Golang String EqualFold

func EqualFold(s, t string) bool

EqualFold is a case-insensitive way of comparing two strings in Golang. The Function returns bool value, it checks for equality in both the strings.

Example:

fmt.Println(strings.EqualFold("Golang", "Golang"))
fmt.Println(strings.EqualFold("Golang", "Go"))
fmt.Println(strings.EqualFold("Golang", "goLANG"))
fmt.Println(strings.EqualFold("Golang", "go"))

Output:

true
false
true
false

Read datatypes in Golang to have better understanding of string comparison in Golang.

Learn more about Golang Strings Package from the official Documentation.