How to check Aadhar number is valid or not using Regular Expression

Last Updated : 04 Feb, 2021

Given string str, the task is to check whether the given string is a valid Aadhar number or not by using Regular Expression. The valid Aadhar number must satisfy the following conditions:

It should have 12 digits.
It should not start with 0 and 1.
It should not contain any alphabet and special characters.
It should have white space after every 4 digits.

Examples:

Input: str = “3675 9834 6012”
Output: true
Explanation:
The given string satisfies all the above mentioned conditions. Therefore, it is a valid Aadhar number.
Input: str = “3675 9834 6012 8”
Output: false
Explanation:
The given string contains 13 digits. Therefore, it is not a valid Aadhar number.

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 Aadhar number as mentioned below:

regex = “^[2-9]{1}[0-9]{3}\\s[0-9]{4}\\s[0-9]{4}$”;

Where:
- ^ represents the starting of the string.
- [2-9]{1} represents the first digit should be any from 2-9.
- [0-9]{3} represents the next 3 digits after the first digit should be any digit from 0-9.
- \\s represents white space.
- [0-9]{4} represents the next 4 digits should be any from 0-9.
- \\s represents white space.
- [0-9]{4} represents the next 4 digits should be any from 0-9.
- $ 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
// Aadhar number using Regular Expression
#include <iostream>
#include <regex>
using namespace std;
 
// Function to validate the Aadhar number.
bool isValidAadharNumber(string str)
{
 
  // Regex to check valid Aadhar number.
  const regex pattern("^[2-9]{1}[0-9]{3}\\s[0-9]{4}\\s[0-9]{4}$");
 
  // If the Aadhar number
  // is empty return false
  if (str.empty())
  {
     return false;
  }
 
  // Return true if the Aadhar number
  // matched the ReGex
  if(regex_match(str, pattern))
  {
    return true;
  }
  else
  {
    return false;
  }
}
 
// Driver Code
int main()
{
  // Test Case 1:
  string str1 = "3675 9834 6015";
  cout << isValidAadharNumber(str1) << endl;
 
  // Test Case 2:
  string str2 = "4675 9834 6012 8";
  cout << isValidAadharNumber(str2) << endl;
 
  // Test Case 3:
  string str3 = "0175 9834 6012";
  cout << isValidAadharNumber(str3) << endl;
 
  // Test Case 4:
  string str4 = "3675 98AF 60#2";
  cout << isValidAadharNumber(str4) << endl;
 
  // Test Case 5:
  string str5 = "417598346012";
  cout << isValidAadharNumber(str5) << endl;
  return 0;
}
 
// This code is contributed by yuvraj_chandra

Java

// Java program to check valid
// Aadhar number using regex.
 
import java.util.regex.*;
class GFG {
 
    // Function to validate Aadhar number.
    public static boolean
    isValidAadharNumber(String str)
    {
        // Regex to check valid Aadhar number.
        String regex
            = "^[2-9]{1}[0-9]{3}\\s[0-9]{4}\\s[0-9]{4}$";
 
        // Compile the ReGex
        Pattern p = Pattern.compile(regex);
 
        // If the string is empty
        // return false
        if (str == null) {
            return false;
        }
 
        // Pattern class contains matcher() method
        // to find matching between given string
        // and regular expression.
        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 = "3675 9834 6015";
        System.out.println(isValidAadharNumber(str1));
 
        // Test Case 2:
        String str2 = "4675 9834 6012 8";
        System.out.println(isValidAadharNumber(str2));
 
        // Test Case 3:
        String str3 = "0175 9834 6012";
        System.out.println(isValidAadharNumber(str3));
 
        // Test Case 4:
        String str4 = "3675 98AF 60#2";
        System.out.println(isValidAadharNumber(str4));
 
        // Test Case 5:
        String str5 = "417598346012";
        System.out.println(isValidAadharNumber(str5));
    }
}

Python3

# Python3 program to validate
# Aadhar number using regex.
import re
 
# Function to validate Aadhar
# number.
def isValidAadharNumber(str):
 
    # Regex to check valid
    # Aadhar number.
    regex = ("^[2-9]{1}[0-9]{3}\\" +
             "s[0-9]{4}\\s[0-9]{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 = "3675 9834 6015"
print(isValidAadharNumber(str1))
 
# Test Case 2:
str2 = "4675 9834 6012 8"
print(isValidAadharNumber(str2))
 
# Test Case 3:
str3 = "0175 9834 6012"
print(isValidAadharNumber(str3))
 
# Test Case 4:
str4 = "3675 98AF 60#2"
print(isValidAadharNumber(str4))
 
# Test Case 5:
str5 = "417598346012"
print(isValidAadharNumber(str5))
 
# This code is contributed by avanitrachhadiya2155

Output:

true
false
false
false
false

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