Question

Hello I am trying to write a program in python that asks the user to input a set of numbers of 1’s and 0’s and I want the program to tell me if I have and even number of zeros or an odd number of zeros or no zero’s at all. Thanks for your help!!

forstate = "start"
curstate = "start"
trans = "none"
value = 0


print "Former state....:", forstate
print "Transition....:", trans
print "Current state....", curstate
    while curstate != "You hav and even number of zeros":
        trans = raw_input("Input a 1 or a 0: ")
        if trans == "0" and value <2:
            value = value + 1
            forstate = curstate
        elif trans == "1" and value < 2:
            value = value + 0
            forstate = curstate
        curstate = str(value) + "  zeros"
        if value >= 2:
            curstate = "You have and even number of zeros"
        print "former state ...:", forstate
        print "Transition .....:", trans
        print "Current state....", curstate

Answer 1

Looks like you’re trying to do a finite state machine?

try:
    inp = raw_input
except NameError:
    inp = input

def getInt(msg):
    while True:
        try:
            return int(inp(msg))
        except ValueError:
            pass

START, ODD, EVEN = range(3)
state_next = [ODD, EVEN, ODD]
state_str  = ['no zeros yet', 'an odd number of zeros', 'an even number of zeros']

state = START
while True:
    num = getInt('Enter a number (-1 to exit)')

    if num==-1:
        break
    elif num==0:
        state = state_next[state]

    print 'I have seen {0}.'.format(state_str[state])

Edit:

try:
    inp = raw_input
except NameError:
    inp = input

START, ODD, EVEN = range(3)
state_next = [ODD, EVEN, ODD]
state_str  = ['no zeros yet', 'an odd number of zeros', 'an even number of zeros']

def reduce_fn(state, ch):
    return state_next[state] if ch=='0' else state

state = reduce(reduce_fn, inp('Enter at own risk: '), START)
print "I have seen " + state_str[state]