How can I assign a pandas dataframe to a class variable?-CodePudding

I have different methods in my class which are using the same pandas dataframe. Instead of passing the same dataframe as an argument to each method, is there a way I can declare the dataframe as a class variable so that all the methods can share it.

I tried the solution given here but couldn't make it work. Assign a pandas dataframe to an object as a static class variable - memory use (Python)

An example of what I am trying to do is

import pandas as pd
df_temp = pd.DataFrame()
df_temp = some_df.copy()     #Assume that I am copying some_df to df_temp

class Weather:
  # I tried using the below and not pass the dataframe to my methods but it didnt work.
  # df = df_temp
  def __init__(self, baseyear):
    self.baseyear = baseyear
   
  def HU_monthly(self, df, month):
    df_HU = df.groupby(['Station','Year','Month'])['Heat Units'].sum().round(2).reset_index()
    return(df_HU)
  
  def HU_range(self, df, first_month, last_month):
    df_between_months = df[(first_month <=df['Month'])&(df['Month']<=last_month)]
    return(df_between_months)

monthly = Weather(2000)
df_1 = monthly.HU_monthly(df_temp, 8)

ranger = Weather(2010)
df_2 = ranger.HU_range(df_temp, 5, 10)

The dataframe(df_temp) I am passing as an argument is same for both the cases, what is the best way of eliminating the need to pass it?

CodePudding user response：

You can pass your dataframe while constructing the object and assign it into an instance variable like this:

class Weather:
    def __init__(self, df):
        self.df = df

Then you can access the dataframe in all your methods like this:

def HU_monthly(self, month):
    df_HU = self.df.groupby(['Station','Year','Month'])['Heat Units'].sum().round(2).reset_index()
    return(df_HU)

Create your class object as following:

weather = Weather(df)