automate.py

Created on April 19, 2020
1.42 KB
Automate reconnaissant ou non un mot.
# fichier : automate.py
#  auteur : Pascal CHAUVIN
#    date : 2020/04/19

class Automate(object):

  def __init__(self, nombre_etats):
    self.__transitions = [{} for i in range(nombre_etats)]
    self.__acceptes = [False] * nombre_etats

  def arc(self, source, etiquette, cible):
    self.__transitions[source][etiquette] = cible

  def etat_final(self, etat):
    self.__acceptes[etat] = True

  def reconnaitre(self, mot):
    erreur = False

    etat = 0 # etat initial
    for etiquette in mot:
      if etiquette in self.__transitions[etat]:
        etat = self.__transitions[etat][etiquette]
      else:
        erreur = True

    if erreur:
      return False
    else:
      return self.__acceptes[etat]

def exemple():

  a = Automate(4)

  a.arc(0, 'a', 0)
  a.arc(0, 'd', 1)
  a.arc(1, 'a', 1)
  a.arc(1, 'e', 1)
  a.arc(1, 'b', 2)
  a.arc(2, 'c', 1)
  a.arc(2, 'i', 2)
  a.arc(2, 'f', 3)

  a.etat_final(3)

  print(a.reconnaitre('albert')) # .......... False
  print(a.reconnaitre('adecif')) # .......... False
  print(a.reconnaitre('adebif')) # .......... True
  print(a.reconnaitre('debif')) # ........... True
  print(a.reconnaitre('aaaadaaeebiif')) # ... True
  print(a.reconnaitre('daa')) # ............. False

  print("choisir un mot (ou vide) :")

  fini = False
  while not fini:
    s = str(input(">>>"))
    fini = (len(s) == 0)
    if not fini:
      print(a.reconnaitre(s))
  print("fin")
  
exemple()