text: The url_for() function is very useful for dynamically building a URL for a specific function. The function accepts the name of a function as first argument, and one or more keyword arguments, each corresponding to the variable part of URL.
  The following script demonstrates use of url_for() function.
  from flask import Flask, redirect, url_for app = Flask(__name__) @app.route('/admin') def hello_admin(): return 'Hello Admin' @app.route('/guest/<guest>') def hello_guest(guest): return 'Hello %s as Guest' % guest @app.route('/user/<name>') def hello_user(name): if name =='admin': return redirect(url_for('hello_admin')) else: return redirect(url_for('hello_guest',guest = name)) if __name__ == '__main__': app.run(debug = True)
  The above script has a function user(name) which accepts a value to its argument from the URL.
  The User() function checks if an argument received matches ‘admin’ or not. If it matches, the application is redirected to the hello_admin() function using url_for(), otherwise to the hello_guest() function passing the received argument as guest parameter to it.
  Save the above code and run from Python shell.
  Open the browser and enter URL as −
  The application response in browser is −
  Hello Admin
  Enter the following URL in the browser −
  The application response now changes to −
  Hello mvl as Guest