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Validate week days using Regular Expression

Validate Gender using Regular Expressions

Given some Weekdays, the task is to check if they are valid or not using regular expressions. 

Rules for the valid Weekdays :

  • It should contain specific only words as a string. They are mentioned below:
    • Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, and Sunday.
    • Mon, Tues, Wed, Thurs, Fri, Sat, Sun. 
    • Mon., Tues., Wed., Thurs., Fri., Sat., Sun. 
    • mon, tues, wed, thurs, fri, sat, sun.

Examples:

Input: “Monday”
Output: True

Input: Payday
Output: False

Approach: The problem can be solved using regular expression based on the following idea:

Create a regex pattern to validate the number as written below:   
regex= “^(sun|Sun|mon|Mon|t(ues|hurs)|(T(ues|hurs))|Fri|fri)(day|\.)?$|wed(\.|nesday)?$|Wed(\.|nesday)?$|Sat(\.|urday)?$|sat(\.|urday)?$|t((ue?)|(hu?r?))\.?$|T((ue?)|(hu?r?))\.?$“

Where,

  • ^ : This indicates the start of the string.
  • $ :End of the string.
  • | : OR

Follow the below steps to implement the idea:

  • Create a regex expression for Weekdays.
  • Use Pattern class to compile the regex formed.
  • Use the matcher function to check whether the Weekday is valid or not.
  • If it is valid, return true. Otherwise, return false.

Below is the implementation of the above approach:

C++




// C++ program to validate the
// Weekday using Regular
// Expression
 
#include <bits/stdc++.h>
#include <regex>
using namespace std;
 
// Function to validate the
// Weekday
string isValid_WeekDay(string str)
{
    // Regex to check valid weekday
    const regex pattern(
        "^(sun|Sun|mon|Mon|t(ues|hurs)|(T(ues|hurs))|Fri|"
        "fri)(day|\.)?$|wed(\.|nesday)?$|Wed(\.|nesday)?$|"
        "Sat(\.|urday)?$|sat(\.|urday)?$|t((ue?)|(hu?r?))"
        "\.?$|T((ue?)|(hu?r?))\.?$");
 
    // If the  str
    // is empty return false
    if (str.empty()) {
        return "false";
    }
 
    // Return true if the str
    // matched the ReGex
    if (regex_match(str, pattern)) {
        return "true";
    }
    else {
        return "false";
    }
}
 
// Driver Code
int main()
{
    // Test Case 1:
    string str1 = "Sunday";
    cout << isValid_WeekDay(str1) << endl;
 
    // Test Case 2:
    string str2 = "Monday";
    cout << isValid_WeekDay(str2) << endl;
 
    // Test Case 3:
    string str3 = "Tues.";
    cout << isValid_WeekDay(str3) << endl;
 
    // Test Case 4:
    string str4 = "Payday";
    cout << isValid_WeekDay(str4) << endl;
 
    // Test Case 5:
    string str5 = "Friday";
    cout << isValid_WeekDay(str5) << endl;
 
    // Test Case 6:
    string str6 = "Birthday";
    cout << isValid_WeekDay(str6) << endl;
 
    return 0;
}
 






                        









Java














                                    




                                    

                                    




                                    




                                    

                                    

                                    
                                




















// Java program to validate the


// Weekday using Regular Expression


 


import java.util.regex.*;


 


class GFG {


    // Function to validate the


    // Weekday


    public static boolean isValid_WeekDay(String str)


    {


 


        // Regex to check valid weekday


        String regex


            = "^(sun|Sun|mon|Mon|t(ues|hurs)|(T(ues|hurs))|Fri|fri)(day|\\.)"


              + "?$|wed(\\.|nesday)?$|Wed(\\.|nesday)?$|Sat(\\.|urday)"


              + "?$|sat(\\.|urday)?$|t((ue?)|(hu?r?))\\.?$|T((ue?)|(hu?r?))\\.?$";


 


        // Compile the ReGex


        Pattern p = Pattern.compile(regex);


 


        // If the str


        // is empty return false


        if (str == null) {


            return false;


        }


 


        // Pattern class contains matcher()


        // method to find matching between


        // given str using regex


        Matcher m = p.matcher(str);


 


        // Return if the str


        // matched the ReGex


        return m.matches();


    }


 


    // Driver Code.


    public static void main(String args[])


    {


 


        // Test Case 1:


        String str1 = "Sunday";


        System.out.println(isValid_WeekDay(str1));


 


        // Test Case 2:


        String str2 = "Monday";


        System.out.println(isValid_WeekDay(str2));


 


        // Test Case 3:


        String str3 = "Tues.";


        System.out.println(isValid_WeekDay(str3));


 


        // Test Case 4:


        String str4 = "Payday";


        System.out.println(isValid_WeekDay(str4));


 


        // Test Case 5:


        String str5 = "Friday";


        System.out.println(isValid_WeekDay(str5));


 


        // Test Case 6:


        String str6 = "Birthday";


        System.out.println(isValid_WeekDay(str6));


    }


}



















                        







                        









Python3














                                    




                                    

                                    




                                    




                                    

                                    

                                    
                                




















# Python3 program to validate


# Weekday using Regular Expression


 


import re


 


# Function to validate


# Weekday


 


 


def isValid_WeekDay(str):


 


    # Regex to check valid Weekday


    regex = "^(sun|Sun|mon|Mon|t(ues|hurs)|(T(ues|hurs))|Fri|fri)(day|\.)"\


    "?$|wed(\.|nesday)?$|Wed(\.|nesday)?$|Sat(\.|urday)?$|sat(\.|urday)"\


    "?$|t((ue?)|(hu?r?))\.?$|T((ue?)|(hu?r?))\.?$"


 


    # 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


if __name__ == '__main__':


 


    # Test Case 1:


    str1 = "Sunday"


    print(isValid_WeekDay(str1))


 


    # Test Case 2:


    str2 = "Monday"


    print(isValid_WeekDay(str2))


 


    # Test Case 3:


    str3 = "Tues."


    print(isValid_WeekDay(str3))


 


    # Test Case 4:


    str4 = "Payday"


    print(isValid_WeekDay(str4))


 


    # Test Case 5:


    str5 = "Friday"


    print(isValid_WeekDay(str5))


 


    # Test Case 6:


    str6 = "Birthday"


    print(isValid_WeekDay(str6))



















                        







                        









C#














                                    




                                    

                                    




                                    




                                    

                                    

                                    
                                




















// Include namespace system


using System;


using System.Text.RegularExpressions;


 


public class GFG


{


 


  // Function to validate the


  // Weekday


  public static bool isValid_WeekDay(String str)


  {


 


    // Regex to check valid LEI Code


    var regex = new Regex("^(sun|Sun|mon|Mon|t(ues|hurs)|(T(ues|hurs))|Fri|fri)(day|\\.)"


                          + "?$|wed(\\.|nesday)?$|Wed(\\.|nesday)?$|Sat(\\.|urday)"


                          + "?$|sat(\\.|urday)?$|t((ue?)|(hu?r?))\\.?$|T((ue?)|(hu?r?))\\.?$");


 


    // If the LEI Code


    // is empty return false


    if (str == null)


    {


      return false;


    }


 


    // Pattern class contains matcher()


    // method to find matching between


    // given weekday using regex.


    var m = regex.Match(str);


 


    // Return if the weekday


    // matched the ReGex


    return m.Success;


  }


 


  // Driver Code.


  public static void Main(String[] args)


  {


 


    // Test Case 1:


    var str1 = "Sunday";


    Console.WriteLine(GFG.isValid_WeekDay(str1));


 


    // Test Case 2:


    var str2 = "Monday";


    Console.WriteLine(GFG.isValid_WeekDay(str2));


 


    // Test Case 3:


    var str3 = "Tues.";


    Console.WriteLine(GFG.isValid_WeekDay(str3));


 


    // Test Case 4:


    var str4 = "Payday";


    Console.WriteLine(GFG.isValid_WeekDay(str4));


 


    // Test Case 5:


    var str5 = "Friday";


    Console.WriteLine(GFG.isValid_WeekDay(str5));


 


    // Test Case 6:


    var str6 = "Birthday";


    Console.WriteLine(GFG.isValid_WeekDay(str6));


  }


}


 


// This code is contributed by Potta Lokesh.



















                        







                        









Javascript














                                    




                                    

                                    




                                    




                                    

                                    

                                    
                                




















// Javascript program to validate


// Weekday using Regular Expression


 


// Function to validate the


// Weekday


function isValid_WeekDay(str) {


    // Regex to check valid


    // weekday


    let regex = new RegExp(/^(sun|Sun|mon|Mon|t(ues|hurs)|(T(ues|hurs))|Fri|fri)(day|\.)?$|wed(\.|nesday)?$|Wed(\.|nesday)?$|Sat(\.|urday)?$|sat(\.|urday)?$|t((ue?)|(hu?r?))\.?$|T((ue?)|(hu?r?))\.?$/);


 


    //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 = "Sunday";


console.log(isValid_WeekDay(str1));


 


// Test Case 2:


let str2 = "Monday";


console.log(isValid_WeekDay(str2));


 


// Test Case 3:


let str3 = "Tues.";


console.log(isValid_WeekDay(str3));


 


// Test Case 4:


let str4 = "Payday";


console.log(isValid_WeekDay(str4));


 


// Test Case 5:


let str5 = "Friday";


console.log(isValid_WeekDay(str5));


 


// Test Case 6:


let str6 = "Birthday";


console.log(isValid_WeekDay(str6));



















                        







                        









													
													
												

												
												

													
													
Output


true
true
true
false
true
false



													
													
												

												
												

													
													
Time Complexity: O(N) for each testcase, where N is the length of the given string. 
Auxiliary Space: O(1)  

													
													
												

												
												

													
													
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										#regular-expression
										
										#Technical Scripter 2022
										
										#DSA
										
										#Pattern Searching
										
										#Technical Scripter
										
										#Pattern Searching
										
										

									

									

										

											
										

										

											
											
												Validate Gender using Regular Expressions