Python Finite State Machine Issues (Skipping the Proccessing?)

Question

I'm creating a python program for finite state machine without it being object oriented. However, my processing phase is off. It doesn't even seem to be running through the triple for loop I created, I checked by attempting to print the CurrentState. Any help would be appreciated.

import sys

try: 
    Sfile = open("states.txt","r")
except IOError:
    print "Could not open file", states.txt
    os.kill()
States = []

ReadLine = Sfile.readline()
while ReadLine != "":
    SN, SS, AS = ReadLine.split(",")
    States.append((SN, bool(int(SS)), bool(int(AS))))
    ReadLine = Sfile.readline()

print States, "\n"
Sfile.close()


try:
    Tfile = open("transistions.txt","r")
except IOError:
    print "Could not open file", transitions.txt
    os.kill()
Transitions = []


ReadLine = Tfile.readline()
while ReadLine != "":
    ReadLine = ReadLine.rstrip()
    CS, IN, NS = ReadLine.split(",")
    Transitions.append((CS, IN, NS))
    ReadLine = Tfile.readline()

print Transitions
Tfile.close()

try:
    Strfile = open("strings2.txt","r")
except IOError:
    print "Could not open file", strings2.txt
    os.kill()
Strings = []

ReadLine = Strfile.readline()
while ReadLine != "":
    Readline = ReadLine.rstrip()
    Strings.append(Readline)
    ReadLine = Strfile.readline()

print Strings, '\n'
Strfile.close()

CurrentState = ''
Start = ''
RejectState= ''
AcceptState= ''

for S in Strings:
    if S != '':
            for C in S:
                for (CS, IN, NS) in Transitions:                
                    if CS == CurrentState and IN == C:
                            CurrentState =NS
                            break
                for  (SN, SS, AS) in States:
                    if SN == CurrentState and SS ==C:
                        CurrentState = NS


    if NS == AS:
            NS = AcceptState
            print "String", AcceptState, "is accepted"
            break
    else:
            NS = RejectState
            print "String", RejectState, "is rejected"
            break

Here are my different text files: strings2.txt

01010
1001
010

transitions.txt

Start,0,State1
State1,1,State2
State2,0,State3

states.txt

State1,1,0
State2,0,1
State3,1,0

Answer 1

I copied your code and data, and was able to get this code (slightly modified from yours) working using python2.7:

import sys
import os

try:
    Sfile = open("states.txt","r")
except IOError:
    print "Could not open file", "states.txt"
    sys.exit()
States = []

ReadLine = Sfile.readline()
while ReadLine != "":
    SN, SS, AS = ReadLine.split(",")
    States.append((SN, bool(int(SS)), bool(int(AS))))
    ReadLine = Sfile.readline()

print "States:\n", States, "\n"
Sfile.close()


try:
    Tfile = open("transitions.txt","r")
except IOError:
    print "Could not open file", "transitions.txt"
    sys.exit()
Transitions = []


ReadLine = Tfile.readline()
while ReadLine != "":
    ReadLine = ReadLine.rstrip()
    CS, IN, NS = ReadLine.split(",")
    Transitions.append((CS, IN, NS))
    ReadLine = Tfile.readline()

print "Transitions:\n", Transitions, "\n"
Tfile.close()

try:
    Strfile = open("strings2.txt","r")
except IOError:
    print "Could not open file", strings2.txt
    sys.exit()
Strings = []

ReadLine = Strfile.readline()
while ReadLine != "":
    Readline = ReadLine.rstrip()
    Strings.append(Readline)
    ReadLine = Strfile.readline()

print "Strings:\n", '\n'.join(Strings), '\n'
Strfile.close()

CurrentState = ''
Start = ''
RejectState= ''
AcceptState= ''

for S in Strings:
    if S != '':
            print "String:", S
            for C in S:
                print "Char:", C
                for (CS, IN, NS) in Transitions:
                    if CS == CurrentState and IN == C:
                            CurrentState =NS
                            break
                for  (SN, SS, AS) in States:
                    if SN == CurrentState and SS ==C:
                        CurrentState = NS


    if NS == AS:
            NS = AcceptState
            print "String", AcceptState, "is accepted"
    else:
            NS = RejectState
            print "String", RejectState, "is rejected"

Here is the output I got:

$ python2.7 test.py
States:
[('State1', True, False), ('State2', False, True), ('State3', True, False)]

Transitions:
[('Start', '0', 'State1'), ('State1', '1', 'State2'), ('State2', '0', 'State3')]

Strings:
01010
1001
010

String: 01010
Char: 0
Char: 1
Char: 0
Char: 1
Char: 0
String  is rejected
String: 1001
Char: 1
Char: 0
Char: 0
Char: 1
String  is rejected
String: 010
Char: 0
Char: 1
Char: 0
String  is rejected