How to do string manipulation in URLs?

String manipulation in URLs can involve various tasks such as parsing, encoding, decoding, constructing, and modifying URLs. Here are some common operations and examples in different programming languages:

1. Python

Python provides the `urllib` and `urllib.parse` modules for URL manipulation.

Example: Parsing and constructing URLs using `urllib.parse`.

```
from urllib.parse import urlparse, urlunparse, urlencode, parse_qs

URL parsing
url = “https://www.example.com?name=John&age=30”
parsed_url = urlparse(url)
print(parsed_url.scheme) # Output: https
print(parsed_url.netloc) # Output: www.example.com
print(parsed_url.query) # Output: name=John&age=30

URL encoding
params = {‘name’: ‘John Doe’, ‘city’: ‘New York’}
encoded_params = urlencode(params)
print(encoded_params) # Output: name=John+Doe&city=New+York

URL constructing
new_url = urlunparse((‘https’, ‘www.example.com’, ‘/page’, ‘’, encoded_params, ‘’))
print(new_url) # Output: https://www.example.com/page?name=John+Doe&city=New+York
```

2. JavaScript

JavaScript offers `URL` and `URLSearchParams` APIs for handling URLs.

Example: Using the `URL` and `URLSearchParams` APIs.

```
// URL parsing
let url = new URL;
console.log(url.hostname); // Output: www.example.com
console.log(url.searchParams.get(‘name’)); // Output: John

// URL encoding
let params = new URLSearchParams();
params.append(‘name’, ‘John Doe’);
params.append(‘city’, ‘New York’);
console.log(params.toString()); // Output: name=John+Doe&city=New+York

// URL constructing
let newUrl = new URL;
newUrl.search = params;
console.log(newUrl.toString()); // Output: https://www.example.com/page?name=John+Doe&city=New+York
```

3. Java

Java uses classes like `URI` and `URLEncoder` for URL manipulations.

Example: Using `URI` and `URLEncoder`.

```
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URLEncoder;
import java.io.UnsupportedEncodingException;

public class URLManipulationExample { public static void main(String[] args) throws URISyntaxException, UnsupportedEncodingException { // URL parsing URI uri = new URI; System.out.println(uri.getHost()); // Output: www.example.com System.out.println(uri.getQuery()); // Output: name=John&age=30

// URL encoding String name = URLEncoder.encode(“John Doe”, “UTF-8”); String city = URLEncoder.encode(“New York”, “UTF-8”); System.out.println(“name=” + name + “&city=” + city); // Output: name=John+Doe&city=New+York // URL constructing String newUri = “https://www.example.com/page?” + “name=” + name + “&city=” + city; System.out.println(newUri); // Output: https://www.example.com/page?name=John+Doe&city=New+York } } ```

4. PHP

PHP has functions like `parse_url`, `http_build_query`, and `urlencode` for handling URLs.

Example: Parsing, encoding, and constructing URLs using PHP.

```
// URL parsing
$url = “https://www.example.com/page?name=John&age=30”;
$parsed_url = parse_url($url);
print_r($parsed_url[‘host’]); // Output: www.example.com
parse_str($parsed_url[‘query’], $query_params);
print_r($query_params[‘name’]); // Output: John

// URL encoding
$params = array(‘name’ => ‘John Doe’, ‘city’ => ‘New York’);
$encoded_params = http_build_query($params);
echo $encoded_params; // Output: name=John+Doe&city=New+York

// URL constructing
$new_url = “https://www.example.com/page?” . $encoded_params;
echo $new_url; // Output: https://www.example.com/page?name=John+Doe&city=New+York
?>
```

Reliable Sources
1. Python urllib.parse Documentation: [docs.python.org](https://docs.python.org/3/library/urllib.parse.html)
2. JavaScript MDN Web Docs for URL: [developer.mozilla.org](https://developer.mozilla.org/en-US/docs/Web/API/URL)
3. Java URI class documentation: [docs.oracle.com](https://docs.oracle.com/javase/8/docs/api/java/net/URI.html)
4. PHP parse\_url and urlencode Documentation: [php.net](https://www.php.net/manual/en/function.parse-url.php), [php.net](https://www.php.net/manual/en/function.urlencode.php)

Using these examples, you can effectively perform string manipulations in URLs across different programming environments.