How to validate MAC address using Regular Expression

Last Updated : 22 Dec, 2022

Given string str, the task is to check whether the given string is a valid MAC address or not by using Regular Expression.

A valid MAC address must satisfy the following conditions:

It must contain 12 hexadecimal digits.

One way to represent them is to form six pairs of the characters separated with a hyphen (-) or colon(:). For example, 01-23-45-67-89-AB is a valid MAC address.

Another way to represent them is to form three groups of four hexadecimal digits separated by dots(.). For example, 0123.4567.89AB is a valid MAC address.

Examples:

Input: str = “01-23-45-67-89-AB”;
Output: true
Explanation:
The given string satisfies all the above mentioned conditions. Therefore, it is a valid MAC address.

Input: str = “01-23-45-67-89-AH”;
Output: false
Explanation:
The given string contains ‘H’, the valid hexadecimal digits should be followed by letter from a-f, A-F, and 0-9. Therefore, it is not a valid MAC address.

Input: str = “01-23-45-67-AH”;
Output: false
Explanation:
The given string has five groups of two hexadecimal digits. Therefore, it is not a valid MAC address.

Approach: The idea is to use Regular Expression to solve this problem. The following steps can be followed to compute the answer.

Get the String.
Create a regular expression to check valid MAC address as mentioned below:

regex = “^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})|([0-9a-fA-F]{4}\\.[0-9a-fA-F]{4}\\.[0-9a-fA-F]{4})$”;

Where:
- ^ represents the starting of the string.
- ([0-9A-Fa-f]{2}[:-]){5} represents the five groups of two hexadecimal digits separated by hyphens (-) or colons (:)
- ([0-9A-Fa-f]{2}) represents the one groups of two hexadecimal digits.
- | represents the or.
- ( represents the starting of the group.
- [0-9a-fA-F]{4}\\. represents the first part of four hexadecimal digits separated by dots (.).
- [0-9a-fA-F]{4}\\. represents the second part of four hexadecimal digits separated by dots (.).
- [0-9a-fA-F]{4} represents the third part of four hexadecimal digits.
- ) represents the ending of the group.
- $ represents the ending of the string.
Match the given string with the Regular Expression. In Java, this can be done by using Pattern.matcher().
Return true if the string matches with the given regular expression, else return false.

Below is the implementation of the above approach:

C++

// C++ program to validate the
// MAC address
// using Regular Expression
#include <iostream>
#include <regex>
using namespace std;
 
// Function to validate the MAC address
bool isValidMACAddress(string str)
{
 
    // Regex to check valid MAC address
    const regex pattern(
    "^([0-9A-Fa-f]{2}[:-]){5}"
      "([0-9A-Fa-f]{2})|([0-9a-"
    "fA-F]{4}\\.[0-9a-fA-F]"
      "{4}\\.[0-9a-fA-F]{4})$");
 
    // If the MAC address
    // is empty return false
    if (str.empty()) 
    {
        return false;
    }
 
    // Return true if the MAC address
    // matched the ReGex
    if (regex_match(str, pattern)) 
    {
        return true;
    }
    else
    {
        return false;
    }
}
 
// Driver Code
int main()
{
    // Test Case 1:
    string str1 = "01-23-45-67-89-AB";
    cout << isValidMACAddress(str1) << endl;
 
    // Test Case 2:
    string str2 = "01:23:45:67:89:AB";
    cout << isValidMACAddress(str2) << endl;
 
    // Test Case 3:
    string str3 = "0123.4567.89AB";
    cout << isValidMACAddress(str3) << endl;
 
    // Test Case 4:
    string str4 = "01-23-45-67-89-AH";
    cout << isValidMACAddress(str4) << endl;
 
    // Test Case 5:
    string str5 = "01-23-45-67-AH";
    cout << isValidMACAddress(str5) << endl;
 
    return 0;
}
 
// This code is contributed by yuvraj_chandra

Java

// Java program to validate
// MAC address using
// regular expression
 
import java.util.regex.*;
class GFG {
 
    // Function to validate
    // MAC address
    // using regular expression
    public static boolean isValidMACAddress(String str)
    {
        // Regex to check valid
        // MAC address
        String regex = "^([0-9A-Fa-f]{2}[:-])"
                       + "{5}([0-9A-Fa-f]{2})|"
                       + "([0-9a-fA-F]{4}\\."
                       + "[0-9a-fA-F]{4}\\."
                       + "[0-9a-fA-F]{4})$";
 
        // Compile the ReGex
        Pattern p = Pattern.compile(regex);
 
        // If the string is empty
        // return false
        if (str == null)
        {
            return false;
        }
 
        // Find match between given string
        // and regular expression
        // uSing Pattern.matcher()
 
        Matcher m = p.matcher(str);
 
        // Return if the string
        // matched the ReGex
        return m.matches();
    }
 
    // Driver code
    public static void main(String args[])
    {
 
        // Test Case 1:
        String str1 = "01-23-45-67-89-AB";
        System.out.println(isValidMACAddress(str1));
 
        // Test Case 2:
        String str2 = "01:23:45:67:89:AB";
        System.out.println(isValidMACAddress(str2));
 
        // Test Case 3:
        String str3 = "0123.4567.89AB";
        System.out.println(isValidMACAddress(str3));
 
        // Test Case 4:
        String str4 = "01-23-45-67-89-AH";
        System.out.println(isValidMACAddress(str4));
 
        // Test Case 5:
        String str5 = "01-23-45-67-AH";
        System.out.println(isValidMACAddress(str5));
    }
}

Python3

# Python3 program to validate
# MAC address using
# using regular expression
import re
 
# Function to validate MAC address.
 
 
def isValidMACAddress(str):
 
    # Regex to check valid
    # MAC address
    regex = ("^([0-9A-Fa-f]{2}[:-])" +
             "{5}([0-9A-Fa-f]{2})|" +
             "([0-9a-fA-F]{4}\\." +
             "[0-9a-fA-F]{4}\\." +
             "[0-9a-fA-F]{4})$")
 
    # Compile the ReGex
    p = re.compile(regex)
 
    # If the string is empty
    # return false
    if (str == None):
        return False
 
    # Return if the string
    # matched the ReGex
    if(re.search(p, str)):
        return True
    else:
        return False
 
# Driver code
 
 
# Test Case 1:
str1 = "01-23-45-67-89-AB"
print(isValidMACAddress(str1))
 
# Test Case 2:
str2 = "01:23:45:67:89:AB"
print(isValidMACAddress(str2))
 
# Test Case 3:
str3 = "0123.4567.89AB"
print(isValidMACAddress(str3))
 
# Test Case 4:
str4 = "01-23-45-67-89-AH"
print(isValidMACAddress(str4))
 
# Test Case 5:
str5 = "01-23-45-67-AH"
print(isValidMACAddress(str5))
 
# This code is contributed by avanitrachhadiya2155

C#

// C# program to validate
// MAC address using
// regular expression
 
using System;
using System.Text.RegularExpressions;
 
class GFG {
 
    // Function to validate
    // MAC address
    // using regular expression
    public static bool isValidMACAddress(string str)
    {
        // Regex to check valid
        // MAC address
        string regex = "^([0-9A-Fa-f]{2}[:-])"
                    + "{5}([0-9A-Fa-f]{2})|"
                    + "([0-9a-fA-F]{4}\\."
                    + "[0-9a-fA-F]{4}\\."
                    + "[0-9a-fA-F]{4})$";
 
        // Compile the ReGex
        Regex p = new Regex(regex);
 
        // If the string is empty
        // return false
        if (str == null)
        {
            return false;
        }
 
        // Find match between given string
        // and regular expression
        // uSing Pattern.matcher()
 
        Match m = p.Match(str);
 
        // Return if the string
        // matched the ReGex
        return m.Success;
    }
 
    // Driver code
    public static void Main()
    {
 
        // Test Case 1:
        string str1 = "01-23-45-67-89-AB";
        Console.WriteLine(isValidMACAddress(str1));
 
        // Test Case 2:
        string str2 = "01:23:45:67:89:AB";
        Console.WriteLine(isValidMACAddress(str2));
 
        // Test Case 3:
        string str3 = "0123.4567.89AB";
        Console.WriteLine(isValidMACAddress(str3));
 
        // Test Case 4:
        string str4 = "01-23-45-67-89-AH";
        Console.WriteLine(isValidMACAddress(str4));
 
        // Test Case 5:
        string str5 = "01-23-45-67-AH";
        Console.WriteLine(isValidMACAddress(str5));
    }
}
 
// This code is contributed by Aman Kumar.

Javascript

// Javascript program to validate
// MAC Address  using Regular Expression
 
// Function to validate the
// MAC_Address  
function isValidMACAddress(str) {
    // Regex to check valid
    // MAC_Address  
    let regex = new RegExp(/^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})|([0-9a-fA-F]{4}.[0-9a-fA-F]{4}.[0-9a-fA-F]{4})$/);
 
    // if str 
    // is empty return false
    if (str == null) {
        return "false";
    }
 
    // Return true if the str
    // matched the ReGex
    if (regex.test(str) == true) {
        return "true";
    }
    else {
        return "false";
    }
}
 
// Driver Code
// Test Case 1:
let str1 = "01-23-45-67-89-AB";
console.log(isValidMACAddress(str1));
 
// Test Case 2:
let str2 = "01:23:45:67:89:AB";
console.log(isValidMACAddress(str2));
 
// Test Case 3:
let str3 = "0123.4567.89AB";
console.log(isValidMACAddress(str3));
 
// Test Case 4:
let str4 = "01-23-45-67-89-AH";
console.log(isValidMACAddress(str4));
 
// Test Case 5:
let str5 = "01-23-45-67-AH";
console.log(isValidMACAddress(str5));
 
// This code is contributed by Rahul Chauhan