Question

The below code is not acting as expected for me.

class stateClass:
  state = 0

states = []
states.append(stateClass)
states.append(stateClass)

def populateStates(states):
  for s in states:
    if s.state == 0
      print 'populating'
      s.state = 1

populateStates(states)

the output is

states array length: 2
populating

this is failing the second time

for s in states:
  if s.state == 0

if conditional is failing the second time although it is a different index in the array and thus the s.state should have been initialized to 0. So I think the loop is not iterating properly.

Anyone know whats wrong?

Answer 1

You don’t need the ;‘s – this isn’t C and co. etc…

class stateClass: 
    state = 0 

Here you’re creating a class level attribute – ie, state is shared by all instances of stateClass.

You’re appending to your list stateClass itself – ie, the definition of the class, not an actual instance of a class…

As soon as you change state in one of them, all instances of stateClass now have that changed value.

You most likely want to be creating instances:

class State(object):
    def __init__(self, number):
        self.state = number

Hawaii = State(50)  
Kentucky = State(23) # (making state numbers up here...) 

my_states = []
my_states.append(Hawaii)
my_states.append(Kentucky)

To then show state, do something like:

print Hawaii.state

If you wanted a property so it avoids explicit setting from outside the class then:

class State(object):
    def __init__(self, number):
        self._state = number
    @property
    def state(self):
        return self._state