python - Method changes all instances of class inside list -

in script have these classes:

class action:   def __init__(self,ac_type,ac_date):     self.ac_type = ac_type     self.ac_date = ac_date  class user:   actions = []   def __init__(self,i_id):     self.ivi_id = i_id   def add(self,act):     self.actions.append(act)   def get_len(self):     return len(self.actions) 

i want create list of "user" elements , add of theme actions. in following way:

for in range(len(data_queue)):   ind = users_id.index(data_queue[i].i_id);   act = action(0,data_queue[i].added)   users[ind].add(act) 

but after running see every action data_queue added every user users. wrong! shall change?

the code using class attribute shared instances of class , class itself.

use instance attribute instead:

class user:     def __init__(self,i_id):         self.ivi_id = i_id         self.actions = []     def add(self,act):         self.actions.append(act)     def get_len(self):         return len(self.actions) 

btw, code using index iterate sequence data_queue. iterate sequence unless need index.

for queue in data_queue:     ind = users_id.index(queue.i_id)     act = action(0, queue.added)     users[ind].add(act)