How to validate MAC address using Regular Expression

27 Jan, 2021
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.
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.
^ 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: 
Java
Python3
C++
// 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})$";         // Compile the ReGex        Pattern p = Pattern.compile(regex);         // If the string is empty        // return false        if (str == null)        {            return false;        }         // Find match between given string        // and regular expression        // uSing Pattern.matcher()         Matcher m = p.matcher(str);         // Return if the string        // matched the ReGex        return m.matches();    }     // Driver code    public static void main(String args[])    {         // Test Case 1:        String str1 = "01-23-45-67-89-AB";        System.out.println(isValidMACAddress(str1));         // Test Case 2:        String str2 = "01:23:45:67:89:AB";        System.out.println(isValidMACAddress(str2));         // Test Case 3:        String str3 = "0123.4567.89AB";        System.out.println(isValidMACAddress(str3));         // Test Case 4:        String str4 = "01-23-45-67-89-AH";        System.out.println(isValidMACAddress(str4));         // Test Case 5:        String str5 = "01-23-45-67-AH";        System.out.println(isValidMACAddress(str5));    }}
# Python3 program to validate# MAC address using# using regular expressionimport re # Function to validate MAC address.  def isValidMACAddress(str):     # Regex to check valid    # MAC address    regex = ("^([0-9A-Fa-f]{2}[:-])" +             "{5}([0-9A-Fa-f]{2})|" +             "([0-9a-fA-F]{4}\\." +             "[0-9a-fA-F]{4}\\." +             "[0-9a-fA-F]{4})$")     # 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++ program to validate the// MAC address// using Regular Expression#include <iostream>#include <regex>using namespace std; // Function to validate the MAC addressbool 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 Codeint 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
true
true
true
false
false
avanitrachhadiya2155
yuvraj_chandra
Computer Networks-IP Addressing
CPP-regex
java-regular-expression
regular-expression
Computer Networks
Pattern Searching
Strings
Strings
Pattern Searching
Computer Networks
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Differences between TCP and UDP
Types of Network Topology
RSA Algorithm in Cryptography
GSM in Wireless Communication
Socket Programming in Python
KMP Algorithm for Pattern Searching
Rabin-Karp Algorithm for Pattern Searching
Check if an URL is valid or not using Regular Expression
Check if a string is substring of another
Boyer Moore Algorithm for Pattern Searching