如何使用一个函数变量转换为另一个函数？

Question

I have two function in Django Templates.

def cart(request, template="shop/cart.html"):
 cart_formset = CartItemFormSet(instance=request.cart)

def checkout_steps(request):

How I use the cart_formset variable in my checkout_steps function. .

Answer 1

You can't. That's what local variables are: they're local to the function they're in. The variable cart_formset does not exist except when cart is executing.

You could return cart_formset from the function and then call cart from checkout_steps to get the value. Or you could store that variable somewhere else. I don't know enough about Django to know where the best place is. Given that what you're doing looks like a shopping cart setup, I would guess that you want to store that info with the session, so you could look at Django's session handling.

Answer 2

How I use the cart_formset variable in my checkout_steps function..

1. If the two functions are related, use a Class (like Shopping) and add cart and checkout_steps as member functions.

    class Shopping(object): def __init__(self): self.cart_formset = None def cart(self, request, template="shop/cart.html"): self.cart_formset = CartItemFormSet(instance=request.cart) def checkout_steps(self, request): #Use self.cart_formset 

2. You can also put the variable cart_formset, as global to make it available globally across the module

    def cart(request, template="shop/cart.html"): global cart_formset cart_formset = CartItemFormSet(instance=request.cart) def checkout_steps(self, request): #Use self.cart_formset 

3. If the order of function evaluation is deterministic then you can use a decorator