Python Dynamic Class Object Names - python

Just a quick question. I've tried Googling this but every time you add "class" to a Python search it gives you classes on Python. D:
I've found threads like this: How can you dynamically create variables via a while loop?
But I don't think that's exactly what I'm looking for since concatenation is also part of the variable.
Here's my while loop:
def main():
counter = 1
while counter <= 3:
print "Name: ",employee[counter].name
print "ID Number: ",employee[counter].id_number
print "Department: ",employee[counter].department
print "Job Title: ",employee[counter].job_title
print #LB
counter = counter + 1
main()
I have my objects set up as:
employee1 = Employee("Susan Meyers", 47899, "Accounting", "Vice President")
employee2 = Employee("Mark Jones", 39119, "IT", "Programmer")
employee3 = Employee("Joy Rogers", 81774, "Manufacturing", "Engineer")
This is the error I receive:
print "Name: ",employee[counter].name
NameError: global name 'employee' is not defined
Obviously I have a class set up as well, but I don't think I need to paste that for this. What I want it to do is go through the loop and change the counter from 1 to 2 to 3. That way it'll loop through all three employees.
Is it possible to do that? I've only ever done this with arrays so I'm not 100% sure I'm on the right track.
Any tips would be great. <3
Chelsea

I think what you are looking for is a list
employees = []
for i in xrange(1,10):
employees.append(employee("some name %s" % i))
employees[4].name

Related

Variable within an instance of a class does not take a new value when it is assigned.

So, I'm working on a command line RPG for the sake of filling time, and re-stretching my Python muscles as I've been out of practice for a couple of years. I used to code in a really functional manner but I'm trying to get my head around object-orientated programming.
Preamble aside, I have an issue where after creating an instance of a class, my class variable is no longer being defined. I've made 2 versions of this which I'll use to demonstrate since I'm finding it hard to articulate.
Below I created a "character" class which I intended to use as a basis for both player characters and npcs. In the first draft I was updating this class, before realising it was going to affect subclasses, when I really just wanted it as a template. Either way, this particular code block worked; it adds the values of 2 dictionaries together, then assigns them to character.characterStats. It then prints them as per displayStats().
from collections import Counter
class character:
def __init__(self, *args, **kwargs):
pass
def __setattr__(self, name, value):
pass
characterRace = ''
characterStats = {}
charLocation = ''
charName = ''
class race:
def __init__(self):
pass
baseStatsDict = {
'Strength' : 5,
'Agility' : 5,
'Toughness' : 5,
'Intelligence' : 5 }
humanStatsDict = {
'Strength' : 1,
'Agility' : 1,
'Toughness' : 1,
'Intelligence' : 1 }
def displayRace():
print("Race: ", character.characterRace, "\n")
def displayStats():
for stat, value in character.characterStats.items():
print(stat, "=", value)
print("\n")
def raceSelection():
playerInput = input("I am a ")
playerInput
playerLower = playerInput.lower()
while "human" not in playerLower:
if "human" in playerLower:
character.characterStats = dict(Counter(race.baseStatsDict)+Counter(race.humanStatsDict))
character.characterRace = 'Human'
break
playerInput = input()
playerInput
playerLower = playerInput.lower()
playerChar = character()
raceSelection()
displayRace()
displayStats()
And this was the output:
Race: Human
Strength = 6
Agility = 6
Toughness = 6
Intelligence = 6
This however is the new code when I tried to tidy it up and turn the class into the template it was meant to be, and started using the class instance playerChar which for whatever reason can't assign the new value to playerChar.characterStats. playerChar.displayStats() prints the characterRace and characterStats variables as empty, even though they are assigned when the player enters the value human.
from collections import Counter
class character:
characterRace = ''
characterStats = {}
def __init__(self):
pass
def displayRace(self):
print("Race: ", self.characterRace, "\n")
def displayStats(self):
for stat, value in self.characterStats.items():
print(stat, "=", value)
print("\n")
class race:
def __init__(self):
pass
baseStatsDict = {
'Strength' : 5,
'Agility' : 5,
'Toughness' : 5,
'Intelligence' : 5 }
humanStatsDict = {
'Strength' : 1,
'Agility' : 1,
'Toughness' : 1,
'Intelligence' : 1 }
def raceSelection():
playerInput = input("I am a ")
playerInput
playerLower = playerInput.lower()
while "human" not in playerLower:
if "human" in playerLower:
playerChar.characterStats = dict(Counter(race.baseStatsDict)+Counter(race.humanStatsDict))
playerChar.characterRace = 'Human'
break
playerInput = input()
playerInput
playerLower = playerInput.lower()
playerChar = character()
raceSelection()
playerChar.displayRace()
playerChar.displayStats()
So this will output:
Race:
\n
\n
\n
So I know it's able to draw from the class race dictionaries and add their contents together as from the previous code. If I try and print the player.x characteristics it won't throw any errors so it recognises they exist. If anyone could explain to me what's going wrong and why in this new iteration, I'd be very grateful.
EDIT: So a friend and I have tried passing the class as an argument of raceSelection(), we've tried printing a string after each call/update of a variable and we've tried entering a string into the variable, printing it, then redefining the variable with a new string.
Input:
class character:
charRace = ''
charStats = {}
charLocation = ''
charName = ''
charString = "Cole said define a string."
Within the if statements:
if "human" in playerLower:
print("Oh, you're just a really ugly human.")
playerChar.charStats = dict(Counter(race.baseStatsDict)+Counter(race.humanStatsDict))
playerChar.charRace = 'Ugly Human'
print("playerChar.charString = ", playerChar.charString)
playerChar.charString = "Redefine."
print("playerChar.charString = ", playerChar.charString)
break
Output:
Oh, you're just a really ugly human.
playerChar.charString = Cole said define a string.
playerChar.charString = Cole said define a string.
Race:
It should not be character.characterStats.items(), but self.characterStats.items(). Similarly for all other values that belong to one, specific character.
Using the name of the class assigns a value that belongs to the class, and is the same for all objects you create. Lookup instance vs class attributes.
So, after trying to move the variables in and out of __init__, trying setattr(), trying to pass any sort of argument through the class just so it had some data, trying to run the instance of the class through a function, none of those solutions came to work in the end.
The solution turned out to be to create a subclass of character and manipulate that instead. I figured this would be alright as well since the player character will mutate throughout gameplay, and will never see further subclasses of itself.

dynamic instances of a class object overwriting each other

I have a simple class that stores simple data. The class is as follows.
class DataFormater:
def __init__(self, N, P, K, price):
self.N = N
self.P = P
self.K = K
self.price = price
The code that calls this class is
from DataFormater import DataFormater
#global variables
ObjectList = [0,1,2,3,4,5,6,7,8,9,10,
11,12,13,14,15,16,17,18,19,20,
21,22,23,24,25,26,27,28,29,30,
31,32,33,34,35,36,37,38,39,40,
41,42,43,44,45,46,47,48,49,50]
ObjectListCounter = 0
# main
print "enter you N-P-K values, followed by a coma, then the price"
print "example ----> 5 5 5 %50 "
print "return as many values as you want to sort, then enter, 'done!' when done."
while True:
RawData = raw_input()
if RawData == 'done!':
break
else:
ObjectList[ObjectListCounter] = DataFormater
ObjectList[ObjectListCounter].N = int(RawData[0])
# very simple test way of putting first indice in ObjectList[ObjectListCounter].N
ObjectListCounter += 1
print ObjectList[0].N
print ObjectList[1].N
My idea is that ObjectList[0] would create that object '1' that I could call with 1.N
But, when I call these, it seems that I have overwritten the previous instances.
this is what prints...
return as many values as you want to sort, then enter, 'done!' when done.
12
1
done!
1
1
Thanks so much! And I know that my post is messy, I don't exactly know how to make it more "pretty"
So, it looks like you are assigning the actual class (instead of an instance of the class) in your loop. Where you do this:
ObjectList[ObjectListCounter] = DataFormater
I think what you actually want is this
ObjectList[ObjectListCounter] = DataFormater(...insert args here....)
EDIT to address the comments:
Your class init method looks like this:
def __init__(self, N, P, K, price):
That means that to create an instance of your class, it would look like this:
my_formater = DataFormater(1, 2, 3, 4)
You would then be able to access my_formater.N which would have a value of 1.
What you are trying to do instead is access a CLASS level attribute, DataFormater.N. This is generally used in situations where you have a constant variable that does not change between instances of the class. For example:
class DataFormater():
CONSTANT_THING = 'my thing that is always the same for every instance'
You would then be able to access that variable directly from the class, like this:
DataFormater.CONSTANT_THING
I hope that clears things up.

Python Update random field choice function from OrderedDict Class

I'm trying to do a script that choose a string and update a current field, but for some reason the code doesn't update the last value when calling my changerandom function in the Greeting class.
...[snip]...
class Greeting(Packet):
fields = OrderedDict([
("Morning", "Hi"),
("Afternoon", "Good Afternoon!"),
("Evening", "Good Evening!"),
])
def change(self):
self.fields["Morning"] = "Good morning!"
def changerandom(self, n = 1):
function=[
{self.fields["Morning"]: "Hello!"},
{self.fields["Morning"]: "Bonjorno!"},
{self.fields["Morning"]: "Hola!"},
]
result = {}
for i in range(n):
result.update(choice(function))
print "Updated string:",result
return result
text = Greeting()
print text
text.change()
print text
text.changerandom()
print text
My code return the following:
Hi
Good morning!
Updated string: {'Good morning!': 'Hola!'}
Good morning!
While it should have returned:
Hi
Good morning!
Hola!
I'm not sure what i'm missing here, I don't see why I cannot update the last field.
Any help would be greatly appreciated!
The problem is that you're returning a result, without assigning it anywhere.
You also use the value of fields, rather than the key. So, your code should be something like
def changerandom(self, n = 1):
function=[
{"Morning": "Hello!"},
{"Morning": "Bonjorno!"},
{"Morning": "Hola!"},
]
for i in range(n):
result = choice(function)
self.fields.update(result)
print "Updated string:",result
return result
Note that we're using self.fields.update, and we're no longer returning anything.
Generally, it's good practice for your functions and methods to return something, or change something, but never both.

How to save a function with python (3.2)

Just started learning python (3.2) and have a question. I have created a some code that creates some stats (as in health, magic etc etc) and the numbers are randomly generated. Here is the code...
def stats ():
print ()
print ('Some text.')
done = False
while not done :
charname = input(str('What is the name of the character? '))
hp = random.randint(5,20)
mp = random.randint(4,20)
stre = random.randint(3,20)
agi = random.randint(3,20)
spd = random.randint(3,20)
wis = random.randint(3,20)
intel = random.randint(3,20)
cha = random.randint(3,20)
print (charname)
print ('HP:',hp)
print ('Mana:',mp)
print ('Strength:',stre)
print ('Agility:',agi)
print ('Speed:',spd)
print ('Wisdom:',wis)
print ('Intelligence:',intel)
print ('Charisma:',cha)
print ()
done = input('All done? yes/no ')
if( done == 'yes' ):
done = True
elif(done == 'no'):
done = False
while done :
print ()
print ('Now that your stats are done, you can go on your adventure!')
done = False
Now this works fine, but how could I call on this function again in case I wanted to view the stats again with it keeping the same stats it randomly generated before?
Sorry if the question is bit off. Still all new to programming.
Thank you.
Since you're new to programming, here's some advice on a different way to store your data (without actually coding it for you).
First, define a Character class, with attributes for HP, mana, etc. I don't know if you know about classes yet, but here's an intro. There are various tricks you can do to get around having to explicitly write in the names for HP, mana, etc, but for learning's sake, it's probably better to do them all manually for now.
Then def a random_character() function that creates a Character object with random attributes, defined like how you're doing now, but instead of saving them in different variables that Python doesn't know have anything to do with one another, puts them in a single Character.
Add a __str__ method to the Character class, so that if char is a Character, print(char) prints out the attributes.
If you want to be able to keep track of characters, use pickle to store it in files.
If you have questions about any part of this, just ask. :)
Your function now uses local variables to record the stats you've generated. You'll need to bundle them together into either a dictionary or an object so that you can pass them around as a value.
For example:
def get_stats():
stats = {}
stats['charname'] = input(str('What is the name of the character? '))
stats['hp'] = random.randint(5,20)
stats['mp'] = random.randint(4,20)
stats['stre'] = random.randint(3,20)
stats['agi'] = random.randint(3,20)
stats['spd'] = random.randint(3,20)
stats['wis'] = random.randint(3,20)
stats['intel'] = random.randint(3,20)
stats['cha'] = random.randint(3,20)
return stats
def print_stats(stats):
print (stats['charname'])
print ('HP:',stats['hp'])
print ('Mana:',stats['mp'])
print ('Strength:',stats['stre'])
print ('Agility:',stats['agi'])
print ('Speed:',stats['spd'])
print ('Wisdom:',stats['wis'])
print ('Intelligence:',stats['intel'])
print ('Charisma:',stats['cha'])
print ()
you can use def keyword to declare functions . Def
def stat():
you can call the function like this in your desired location. stat()
If you want easy storage in an external file, you can use the pickle module, and a dictionary of the values you wish to store.
for example:
import pickle
stats={}
stats['hp'] = random.randint(5,20)
stats['mp'] = random.randint(4,20)
stats['stre'] = random.randint(3,20)
stats['agi'] = random.randint(3,20)
stats['spd'] = random.randint(3,20)
stats['wis'] = random.randint(3,20)
stats['intel'] = random.randint(3,20)
stats['cha'] = random.randint(3,20)
#save the stats into the file by using:
pickle.dump(stats,yourstatfile.pkl)
#then to load it again from any program just use:
stats=pickle.load(yourstatfile.pkl) #you assign it to a variable, so if i used the variable 'lol' i would use it as lol['hp'] not stats['hp'] like it was originally used when saving.
#then you can use it just like any other dictionary:
print "your hp: "+str(stats['hp'])

How to change global variables in Python [duplicate]

This question already has answers here:
Using global variables in a function
(25 answers)
Closed 3 years ago.
I am trying to change a variable further down the program. I have a global variable declared at the start of the program and I want to change the variable in different functions down the program. I can do this by declaring the variable inside the function again but I would like to know is there a better way of doing this. Some test code is below to explain what I mean.
ID = 'No'
project = ("Yep"+ID) # ID added with 'No' value which I later want to change
def pro():
ID = "YES"
print ID
def pro1(ID):
# I could declare project again to get this to work, but I would like to avoid this
print project # I want this to print with the new ID number.
if __name__ == '__main__':
pro()
pro1(ID)
Has anyone any ideas, thanks
I have tried the global variable but when I do this the project variable still prints out YepNo instead of YepYES. I want the new variable from the function proto change the variable in the project variable.
To update global variables you could use
global ID
ID="Yes"
before assigning variable to ID = "YES"
But changing ID will be no effect on project variable, project = ("Yep"+ID), because project is already a string
you need to make a function like
def getprojectname(ID):
return project+ID
The whole program may be like this
UPDATE:
... removed
Beware, you're doing it wrong multiple times.
Even though you could use the global statement to change a global (it is discouraged since it's better to use function parameters and return values), that would NOT change other already assigned values. E.g. even though you reassign ID, you would NOT reassign project. Also: your functions return nothing, there's no point in assigning a name to their return value, and it's a BAD habit using an all-uppercase name (ID) for a variable since it's a convention to use them for constants.
This should clarify you the way global works:
myid = ''
project = ("Yep"+myid) #ID added with no value which I later want to change
def mutate_id():
global myid
myid = "YES"
def mutate_project():
global project
project = ("YEP" + myid)
if __name__ == '__main__':
print "myid", myid
print "project ", project
print
mutate_id()
print "myid", myid
print "project ", project
print
mutate_project()
print "myid", myid
print "project ", project
print
But the best way is to do WITHOUT globals:
def get_new_id(old):
return "YES"
def get_new_project(old):
return ("YEP" + myid)
if __name__ == '__main__':
myid = ''
project = ("Yep"+myid)
print "myid", myid
print "project ", project
print
myid = get_new_id(myid)
print "myid", myid
print "project ", project
print
project = get_new_project(project)
print "myid", myid
print "project ", project
print
This will make all code interaction clear, and prevent issues related to global state change.
Use the global statement.
The global statement is a declaration which holds for the entire current code block. It means that the listed identifiers are to be interpreted as globals.
Example: http://www.rexx.com/~dkuhlman/python_101/python_101.html#SECTION004340000000000000000
P.S.
But don't use global too often, see http://www.youtube.com/watch?v=E_kZDvwofHY#t=10m45
In your code you have two problems. The first about changing ID variable, which could be solved by using global.
The second that your code calculate project string and after that project don't know about ID.
To avoid code duplication you can define function to calc project.
So we have:
ID = 'No'
def GetProject():
return "Yep"+ID
def pro():
global ID
ID = "YES"
print ID
print GetProject()
pro()
print GetProject()
You can mutate without reassigning:
variables = {}
def pro():
if variables['ID'] == '':
variables['ID'] = 'default'
Why not use a dictionary?
>>> attr = {'start':'XXX', 'myid':'No'}
>>>
>>> def update_and_show(D, value = None):
... if value: D['myid'] = value
... print D['start'] + ' ' + D['myid']
...
>>> update_and_show(attr)
XXX No
>>> update_and_show(attr, 'Yes')
XXX Yes
>>> update_and_show(attr, 'No')
XXX No
>>>

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