Given a URL as a character string str of size N.The task is to check if the given URL is valid or not.
Examples :
Input : str = “https://www.geeksforgeeks.org/”
Output : Yes
Explanation :
The above URL is a valid URL.
Input : str = “https:// www.geeksforgeeks.org/”
Output : No
Explanation :
Note that there is a space after https://, hence the URL is invalid.
Approach :
An approach using java.net.url class to validate a URL is discussed in the previous post.
Here the idea is to use Regular Expression to validate a URL.
- Get the URL.
- Create a regular expression to check the valid URL as mentioned below:
regex = “((http|https)://)(www.)?”
+ “[a-zA-Z0-9@:%._\\+~#?&//=]{2,256}\\.[a-z]”
+ “{2,6}\\b([-a-zA-Z0-9@:%._\\+~#?&//=]*)”
- The URL must start with either http or https and
- then followed by :// and
- then it must contain www. and
- then followed by subdomain of length (2, 256) and
- last part contains top level domain like .com, .org etc.
- Match the given URL with the regular expression. In Java, this can be done by using Pattern.matcher().
- Return true if the URL matches with the given regular expression, else return false.
Below is the implementation of the above approach:
C++
// C++ program to validate URL// using Regular Expression#include <iostream>#include <regex>using namespace std;// Function to validate URL// using regular expressionbool isValidURL(string url){ // Regex to check valid URL const regex pattern("((http|https)://)(www.)?[a-zA-Z0-9@:%._\\+~#?&//=]{2,256}\\.[a-z]{2,6}\\b([-a-zA-Z0-9@:%._\\+~#?&//=]*)"); // If the URL // is empty return false if (url.empty()) { return false; } // Return true if the URL // matched the ReGex if(regex_match(url, pattern)) { return true; } else { return false; }}// Driver Codeint main(){ if (isValidURL(url)) { cout << "YES"; } else { cout << "NO"; } return 0;}// This code is contributed by yuvraj_chandra |
Java
// Java program to check URL is valid or not// using Regular Expressionimport java.util.regex.*;class GFG { // Function to validate URL // using regular expression public static boolean isValidURL(String url) { // Regex to check valid URL String regex = "((http|https)://)(www.)?" + "[a-zA-Z0-9@:%._\\+~#?&//=]" + "{2,256}\\.[a-z]" + "{2,6}\\b([-a-zA-Z0-9@:%" + "._\\+~#?&//=]*)"; // Compile the ReGex Pattern p = Pattern.compile(regex); // If the string is empty // return false if (url == null) { return false; } // Find match between given string // and regular expression // using Pattern.matcher() Matcher m = p.matcher(url); // Return if the string // matched the ReGex return m.matches(); } // Driver code public static void main(String args[]) { String url if (isValidURL(url) == true) { System.out.println("Yes"); } else System.out.println("NO"); }} |
Python3
# Python3 program to check# URL is valid or not # using regular expression import re# Function to validate URL # using regular expression def isValidURL(str): # Regex to check valid URL regex = ("((http|https)://)(www.)?" + "[a-zA-Z0-9@:%._\\+~#?&//=]" + "{2,256}\\.[a-z]" + "{2,6}\\b([-a-zA-Z0-9@:%" + "._\\+~#?&//=]*)") # 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:if(isValidURL(url) == True): print("Yes")else: print("No")# This code is contributed by avanitrachhadiya2155 |
C#
// C# program to check URL is valid or not//using Regular Expressionsusing System;using System.Text.RegularExpressions;class GFG{ // Main Method static void Main(string[] args) { // Input strings to Match // Valid URL foreach(string s in str) { Console.WriteLine( isValidURL(s) ? "true" : "false"); } Console.ReadKey(); } // method containing the regex public static bool isValidURL(string str) { string strRegex = @"((http|https)://)(www.)?" + "[a-zA-Z0-9@:%._\\+~#?&//=]" + "{2,256}\\.[a-z]" + "{2,6}\\b([-a-zA-Z0-9@:%" + "._\\+~#?&//=]*)"; Regex re = new Regex(strRegex); if (re.IsMatch(str)) return (true); else return (false); }}// This code is contributed by Rahul Chauhan |
Javascript
function isValidURL(str) { if(/^(http(s):\/\/.)[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)$/g.test(str)) { console.log('YES'); } else { console.log('NO'); }} // This code is contributed by Rahul Chauhan |
Output:
Yes
Time Complexity: O (N)
Auxiliary Space: O (1)
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