AttributeError: 'Read_csv' object has no attribute 'datetime_array'

Question

I'm developing a software that reads a csv file and create a list for each column. In another class, I want to plot the data contained in the arrays of the first class.

I get this error:

AttributeError: 'Read_csv' object has no attribute 'datetime_array'

How can I solve it? These are my classes.

Csv_Reader:

import pandas as pd
from datetime import datetime
#from csv import reader

class Read_csv:

def csv_reader(self, file_name):
    
    df = pd.read_csv(file_name, delimiter = ';')
    self.datetime_array = list(map(lambda x: datetime.strptime(x, '%Y-%m-%d %H:%M:%S.%f'), df["DateTime"]))
    self.vet_values_s1 = df["S1"].tolist()
    self.vet_values_s2 = df["S2"].tolist()
    self.vet_values_s3 = df["S3"].tolist()
    print(self.datetime_array, self.vet_values_s1, self.vet_values_s2, self.vet_values_s3)

Data_Plotter:

import numpy
import matplotlib.pyplot as plt
import matplotlib.patches as mpatches
from Csv_Reader import Read_csv

class Data_plotter:
    
def __init__(self, datetime_array, vet_values_s1, vet_values_s2, vet_values_s3):
    self.datetime_array = datetime_array
    self.vet_values_s1 = vet_values_s1
    self.vet_values_s2 = vet_values_s2
    self.vet_values_s3 = vet_values_s3
    

def plot_data(self):
    
    plt.plot(self.vet_values_s1, color = 'green')
    plt.plot(self.vet_values_s2, color = 'red')
    plt.plot(self.vet_values_s3, color = 'blue')
    
    plt.title('Test')
    
    plt.xlabel('DateTime')
    plt.ylabel('Signals Values')
    plt.xticks(numpy.arange(len(self.datetime_array)), self.datetime_array, rotation=90)
    
    green = mpatches.Patch(color='green',label='S1')
    red = mpatches.Patch(color='red',label='S2')
    blue = mpatches.Patch(color='blue',label='S3')
    plt.legend(handles=[green,red,blue])
    
    plt.grid(True)
    
    plt.savefig("Test")

main:

from Csv_Reader import Read_csv
from Data_Plotter import Data_plotter

reader_obj = Read_csv()

Read_csv().csv_reader('Signals_informations.csv')
obj = Data_plotter(reader_obj.datetime_array, reader_obj.vet_values_s1, reader_obj.vet_values_s2, reader_obj.vet_values_s3)
obj.plot_data()

My csv file:

DateTime;S1;S2;S3
2020-07-16 15:11:34.358231;677.0552427707063;787.6245155900142;543.0755073183745
2020-07-16 15:11:34.360247;535.4790551706492;317.65859520197984;218.64223032216418
2020-07-16 15:11:34.362263;451.9436928722545;449.5560971162404;215.33038976545765
2020-07-16 15:11:34.364279;72.31352267938303;251.55939892326035;896.9233907560412
2020-07-16 15:11:34.366295;758.7365312885398;686.7909954314093;303.9852170969752
2020-07-16 15:11:34.368311;593.8244329562257;698.5981983561348;369.11408762777785
2020-07-16 15:11:34.370327;338.56552989499176;469.327619765774;331.0295457896333
2020-07-16 15:11:34.372343;729.3276090259968;690.776181594403;97.6830657885398
2020-07-16 15:11:34.374359;284.58252864976197;569.0028638781417;196.02767689983673
2020-07-16 15:11:34.376375;909.5920826056772;178.28447193362686;240.4015082916274

Answer 1

Change this line:

Read_csv().csv_reader('Signals_informations.csv')

to

reader_obj.csv_reader('Signals_informations.csv')

With Read_csv() you're creating a new object instead of using the one you've already created (reader_obj) and using in the next line.