Golang - 5 different ways of comparing two strings with reasons

Program logic often depends on comparing strings to make a decision. In Go, strings are actually a sequence of bytes, and comparing them involves comparing the individual bytes of the string.

What method to choose

Method	Reason
==, !=	A simple comparison between small strings
strings.Compare()	The recommended way for comparing case-sensitive strings
strings.EqualFold()	The recommended way for comparing case-insensitive strings
strings.Contains()	Comparing case-sensitive substring
strings.Contains() with lowercase	Comparing case-insensitive substrings

How to use == for strings comparison in Golang?

You can check if the string is equal to one another using the == operator.

package main

import (
	"fmt"
)

func main() {

	// Check if the search string and name are same
	name := "Learning Go"
	searchText := "Learning Go"

	if name == searchText {
		fmt.Println("Same strings")
	}
}

You can also use the != to check for inequality in golang.

package main

import (
	"fmt"
)

func main() {
	// Inequality check
	name := "Learning Go"
	searchText := "Test"

	if name != searchText {
		fmt.Println("Different strings")
	}
}

How to compare using strings package in golang?

There is compare method in the strings package which can be used to get an integer value ranging in the following values.

• Compare() returns 0 - string are same
• Compare() returns 1 - first string is bigger
• Compare() returns -1 - first string is lesser

Method definition

func Compare(a, b string) int

Official doc for Contains() method

Example

package main

import (
	"fmt"
	"strings"
)

func main() {

	// Check if the search string and name are same
	name := "Learning Go"
	searchText := "Learning Go"

	if strings.Compare(name, searchText) == 0 {
		fmt.Println("Same strings")
	}

	// Inequality check
	name = "Learning Go"
	searchText = "Test"

	if strings.Compare(name, searchText) != 0 {
		fmt.Println("Different strings")
	}
}

How to compare case-insensitive strings in golang?

The EqualFold method in the strings package can be used for case-insensitive string comparison. This method returns true if the strings are equal otherwise it will return false.

Method definition

func EqualFold(s, t string) bool

Offical docs for EqualFold() method

Example

package main

import (
	"fmt"
	"strings"
)

func main() {

	// Check if the search string and name are same
	name := "LeaRNIng GO"
	searchText := "Learning Go"

	if strings.EqualFold(name, searchText) {
		fmt.Println("Same strings")
	}
}

How to compare substrings in golang?

When you are implementing the search and filtering logic in your go program, you would need to compare the search text with a partial search in your database and return the results of the operation.

You can use the Contains() method in the strings package to do this partial search. It returns true if the substring is present in the other string and false if not.

Method definition

func Contains(s, substr string) bool

Official docs for Contain() method

Example

package main

import (
	"fmt"
	"strings"
)

func main() {

	// Check if the search string is present in name
	name := "Learning Go"
	searchText := "Learn"

	if strings.Contains(name, searchText) {
		fmt.Println("It contains the substring")
	}

}

How to compare case-insensitive substring in golang?

You can use the contains method along with converting all the strings to lowercase to get the case-insensitive substring search in golang

Method definition

func ToLower(s string) string

Official docs for ToLower() method

Example

package main

import (
	"fmt"
	"strings"
)

func main() {

	// Check if the search string is present in name
	name := strings.ToLower("Learning Go")
	searchText := strings.ToLower("learn")

	if strings.Contains(name, searchText) {
		fmt.Println("It contains the substring")
	}
}