从 function 返回多个 obj 的最佳方法

Question

Lets say i have 2 classes, i want to take from class First two dfs, to second class, should I return them and unpack or use sefl.df and do not use return if i want to use those dfs in more than one function in other class?

I can unpack but its only one per program runs and i cannot unpack two times same function.

Import pandas as pd

class First:
  def func(self):
    Df = df.read_csv('my data.csv')
    Df2= Df.copy()

    return Df,Df2

class Second(First):
   def one(self):
      Df,Df2 = self.func()
      DF1=....

   def two(self):
      Df,Df2 = self.func()
      Df2=....

Answer 1

The "best" approach really depends on what you are trying to achieve and what restrictions you are dealing with ( and usually has a significant subjective component ).
It doesn't seem to be clear whether flexibility or efficiency is more important from the information you have given, so here is how I would handle such a situation.

Considering efficiency, my main concern was that every time you call func, you re-read the csv file. From my experience this is rarely necessary, but if you want it as an option, I would do it like this:

import pandas as pd

class First:
    def __init__(self, read_now= True):
        if read_now:
            self.Df, self.Df2 = self.func()

    def func(self):
        Df = pd.read_csv('my data.csv')
        Df2= Df.copy()

        return Df,Df2

class Second(First):

    def one(self, reread= False):
        if reread: 
            Df,Df2 = self.func()
        else: 
            Df, Df2 = self.Df, self.Df2
        # operation

    def two(self, reread= False):
        if reread: 
            Df, Df2 = self.func()
        else: 
            Df, Df2 = self.Df, self.Df2
        # operation

By not rereading everytime, you can make it more efficient and modify the dataframe in memory, but you still have the option of easily rereading the dfs if you really need to.

But as I said, "best" tends to be ambiguous, especially with limited information.