Control the input of the user according to a sample string and get some info from it

Question

I made this Python code that prints a sample string and ensures that the input of the user agrees with the sample, and then do an action with this inputted string, in this case a multiplication table.

I've made this code to practice some Python concepts, and I do not know if I did everything correctly and "in a pythonic way". I'd like to know if there's anything in this code that can be improved and things I could have done otherwise.

import re
from time import sleep 
class StringController(object): 
 def __init__(self, *args, **kwargs): 
 self.regexp = re.compile('(?i)^show me the multiplication table of [0-9]* from [0-9]* to [0-9]*$') 
 def __enter__(self, *args, **kwargs):
 print('Example string: show me the multiplication table of 10 from 5 to 20')
 self.inputedstring = input('Input: ')
 print('-'*50)
 sleep(1)
 return self
 def __exit__(self, exc_type, exc_val, exc_tb):
 if exc_type:
 print('{}: {}'.format(exc_type.__name__, 'You must use the provided string'))
 else:
 print('-'*50)
 del self.inputedstring
if __name__ == '__main__':
 myobject = StringController()
 while True:
 try:
 with myobject as strcon:
 multiplication_table = list(range(int(myobject.inputedstring.split(' ')[8]), int(myobject.inputedstring.split(' ')[10])+1))
 results = list(map(lambda x : x*int(myobject.inputedstring.split(' ')[6]), multiplication_table))
 if myobject.regexp.match(myobject.inputedstring):
 print('\n'.join(str(results) for results in results))
 else:
 raise UserWarning('You must use the provided string')
 except (ValueError, IndexError) as WrongInput:
 print("\n")
 del WrongInput
 finally:
 del strcon

Output:

enter image description here

• Jamal: There's no need for <pre> tags; you should just use indentation. I fixed the &quots as well.

Answer 1

Bug

The regex is flawed, consider this:

>>> print(re.match(pat, 'show me the multiplication table of from to '))
>>> <re.Match object; span=(0, 46), match='show me the multiplication table of from to '>

That is because [0-9]* matches the digit zero, or more times

I suggest to change them with + which will match the digit 1, or more times

pattern = re.compile('(?i)^show me the multiplication table of \d+ from \d+ to \d+$')

Codestyle

1. StringController() seems overly complex

   Basically the same can be achieved with re.match(pattern, input_string)

   It adds a layer of complexity what is not needed, I would just remove the entire class

2. The extraction of numbers can be greatly simplified

   You could use re.findall(r'(\d+)', input) to find the digits in a neater way

   And you could map(int, iterable) to convert them to integers

Alternative

INPUT_REGEX = re.compile('(?i)^show me the multiplication table of \d+ from \d+ to \d+$')
def make_table(user_input):
 step, min_range, max_range = map(int, re.findall('(\d+)', user_input))
 return "\n".join(str(step * t) for t in range(min_range, max_range))
def main():
 while True:
 user_input = input('Example string: show me the multiplication table of 8 from 3 to 8\nInput: ')
 print('-'*50)
 if user_input.lower() in ('q', 'quit', 'exit'):
 exit()
 elif re.match(INPUT_REGEX, user_input):
 print(make_table(user_input))
 else:
 print('Use the provided string')
if __name__ == '__main__':
 main()

Note I added a quit, might be nice for your user to let them exit in a clean way ;)