What is a property object?

Question

I am not new to python, but I have a pretty basic question here.

I was playing around with python and found that there is the type property

>>>          


        

Answer 1

class MyClass:
    def __init__(self,*costs):
        self.costs = costs
    def item_cost(self):
        return sum(self.costs)

now you can do

MyClass(1,2,3,4).item_cost() #prints 10

but we can make it a property

class MyClass:
    def __init__(self,*costs):
        self.costs = costs
    @property
    def item_cost(self):
        return sum(self.costs)

and now we can access it as a simple variable

MyClass(1,2,3,4).item_cost

you could also create a setter for the value with

  ...
   @item_cost.setter
   def set_item_cost(self,value):
         pass #do something with value
  ...
 MyClass(1,2,3,4).item_cost = "yellow"

In general I find them to be sort of an anti-pattern... but some folks like em

(side note you could also make it a property using it as a regular function instead of a decorator MyClass.item_cost_prop = property(MyClass.item_cost) )