如何在Python类函数中隐式传递参数

Question

I was writing a python class and related functions. Suppose following is a class having a function that adds up all values of a numeric list and returns the sum

 alist = [2,3,7,4,7]
 MyClasss(object):
    def __init__(self):
        print("Roses are red")
    def add_list(self,thelist):
         j = 0
         for i in the list:
             j = j+i
    return j 

  a = MyClasss()
  print("sum is ",a.add_list(alist))

The above query will return the sum of the list just fine.

MY QUESTION IS: Is it possible write this query or create a data object in which we do not have to pass the data object in the brackets instead write it something like this

 alist.add_list()

and get the same results. Like we see different functions are available for different data types. Any insights on this will be highly appreciated. Thanks

Answer 1

You can add it to __init__ on construction

class MyClasss(object):
    def __init__(self, theList):
        self.theList = theList
    def add_list(self):
        return sum(self.theList)

>>> a = MyClasss([2,3,7,4,7])
>>> print("sum is ", a.add_list())
23
>>> print("sum is ", a.add_list())
23

Another way to do this is create a partial function from functools.partial and call that:

>>> import functools as ft
>>> a = MyClasss()
>>> a.add_list = ft.partial(a.add_list, [2,3,7,4,7])
>>> a.add_list()
23