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
It sounds like homework, or worse an interview questions, but this will get you started.
def homework(s):
counter = 0
if '0' in s:
for i in s:
if i == '0':
counter = counter + 1
return counter
don't forget this part over here
def odd_or_even_or_none(num):
if num == 0:
return 'This string contains no zeros'
if num % 2 == 0
return 'This string contains an even amount of zeros'
else:
return 'This string contains an odd amount of zeros'
if you call homework and give it a string of numbers it will give you back the number of 0
homework('101110101')
now that you know how many 0s you need to call odd_or_even_or_none with that number
odd_or_even_or_none(23)
so the solution looks like this
txt = input('Feed me numbers: ')
counter = str( homework(txt) )
print odd_or_even_or_none(counter)
try:
inp = raw_input
except NameError:
inp = input
zeros = sum(ch=='0' for ch in inp('Can I take your order? '))
if not zeros:
print "none"
elif zeros%2:
print "odd"
else:
print "even"
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]
The simple solution to your problem is just to count the zeros, then print a suitable message. num_zeros = input_stream.count('0')
If you're going to build a finite state machine to learn how to write one, then you'll learn more writing a generic FSM and using it to solve your particular problem. Here's my attempt - note that all the logic for counting the zeros is encoded in the states and their transitions.
class FSMState(object):
def __init__(self, description):
self.transition = {}
self.description = description
def set_transitions(self, on_zero, on_one):
self.transition['0'] = on_zero
self.transition['1'] = on_one
def run_machine(state, input_stream):
"""Put the input_stream through the FSM given."""
for x in input_stream:
state = state.transition[x]
return state
# Create the states of the machine.
NO_ZEROS = FSMState('No zeros')
EVEN_ZEROS = FSMState('An even number of zeros')
ODD_ZEROS = FSMState('An odd number of zeros')
# Set up transitions for each state
NO_ZEROS.set_transitions(ODD_ZEROS, NO_ZEROS)
EVEN_ZEROS.set_transitions(ODD_ZEROS, EVEN_ZEROS)
ODD_ZEROS.set_transitions(EVEN_ZEROS, ODD_ZEROS)
result = run_machine(NO_ZEROS, '01011001010')
print result.description
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