Creating multiple class instances from a list of names in Python?

Question

Can someone explain to me how to return a new instance of a class by iterating over a list of names and a list of dicts?

I know that I can unpack my dictionary using ** , and I know that I can iterate through my list of dictionaries.

So I attempted to create a for loop function that creates new instances of my Card class for each card in the cardList .

Here is the code I thought would work:

def createCardInstances(x):
    for i in range(len(x)):
        namesOfCards[i] = Card(**cardList[i])
        return namesOfCards[i]

namesOfCards is a list of card names that I would like to turn into instances of the Card class. cardList is a list of the dictionaries that represent cards and their values.

For instance, I can do this:

Knight = Card(**cardList[0])

Which works fine. But, if I'm developing a card game and have upwards of a 100 individual cards or more, I would like to avoid having to write out each card name individually and copy\\pasting the =Card(**cardList[]) code each time.

How do I automate the creation of new instances? Is that even feasible?

---

EDIT:

I'm trying to use the names in namesOfCards to make new instances of Card . It was suggested to me that my next step in learning python while creating a card game was to make it more object oriented.

So my goal right now is to use the names of the cards - saved in the list namesOfCards - to make new instances of Card . ie:

[Knight, Mage, Warrior, ...]

And I want to have the ability to take those and do this:

Knight = Card(**cardList[0])

Mage = Card(**cardList[1])

Warrior = Card(**cardList[2]

and so on and so forth.

Is that possible? Or do I need to use the list comprehension suggestion to store all of the class instances into a list, and then have to access the instances by using new_cards[0].name or new_cards[1].attack ?

Answer 1

you are returning an individual card when you pass it a list? also if cardNames is a list of names you shouldn't be overwriting it with Card objects. You should be able to do something like this?

new_cards = [Card(**card) for card in card_list]  # make new card objects
cards = {card.name: card for card in new_cards}  # dict to ref cards by name 
print cards['Knight'].name

or simply

cards = {card['name']: Card(**card) for card in card_list}

if you are wanting to restrict that cards to only those in namesOfCards . you could

cards = {card['name']: Card(**card) for card in card_list if card['name'] in names_of_cards}

( note : this all assumes that you dont have two cards with the same name)

It is also possible to put those cards into your local namespace like the question asks, but I would highly discourage it. But if you really really want to ...

locals().update(cards)
print Knight.name

Answer 2

make sure that your list contains string like

CARDS = ['Knght', 'Mage'] #and so on

I'm not sure if this is what you need but see the code below:

CARD = ['knight','mage']

class cards:
    def __init__(self, name):
        self.n = name
        self.attack = "attack " + self.n

print knight.attack

using that you can loop through a list or dictionary to create an instance of your class