Question

22.39 LAB 13 C FALL 2019 Overview Demonstrate your ability to use pandas with functions Description Write a program that reads data from an input file using a DataFrame and displays a subset of data using a method Provided Input Files An input file with nearly 200 rows of data about automobiles. The input file has the following format: mpg, cylinders, displacement, horsepower, weight, acceleration, model_year, origin, name 18,9,307,130,3504, 12, 70, usa, chevrolet chevelle malibu 15,8,350,165,3693, 11.5,70, usa, buick skylark 320 18,8,318,150,3436,11,70, usa, plymouth satellite 16,3, 304, 150, 3433, 12, 70, usa,ame rebel sst Objectives The objective of this program is to read data from a file into a DataFrame and use the head method to display a subset of the data. You will also create a function Complete the program as follows: . Read the name of an input file from the user • Open the file • The input file contains information about the fuel economy of a list of vehicles. Open the input file using the pandas read.csvo) method and read the contents of the file into a DataFrame • Prompt the user for two column names • Using DataFrame methods, get the subset of the of the first 5 rows of the two columns specified by the user, using a function The function definition is def get_subset(data_frame, column1, column 2) Pass the DataFrame, column1, and column2 to the function in that order • The function should return the subset of data it is acceptable to have a single statement in your function that simply returns the result of the head method • Display the subset of data

Answer 1

#Version: Python3

#In-built packages
import os

#External packages
import pandas as pd    # pip3 install pandas

def get_subset(data_frame, column1, column2):
   """
   Gives the subset of a csv file with specified column names only (5rows x 2columns).

   Parameters:
       data_frame = Pandas' DataFrame of an input csv file.
       column1 = Selected 1st column to display.
       column2 = Selected 2nd column to display.

   Returns:
       First five(5) rows of the two columns specified.

   Exception:
       If any of the specified column(s) is not there in the data_frame.
   """
   try:
       # head() is for getting only first 5 rows
       return (data_frame[[column1, column2]]).head()
   except Exception as e:
       print ('Specified column(s) are not found')

if __name__ == '__main__':
   csv_file = input('Enter a file name: ')
   # Checking if the input file is a csv or not
   if csv_file.endswith('csv'):
       # Checking if the input file exists or not
       if os.path.exists(csv_file):
           # Reading csv using pandas library
           data_frame = pd.read_csv(csv_file, skipinitialspace=True)
           column1 = input('Enter the first column to display: ')
           column2 = input('Enter the second column to display: ')
           # Assigning get_subset() function value to subset
           subset = get_subset(data_frame, column1, column2)
           print ('First 5 rows of columns %s and %s:' %(column1, column2))
           # Printing the final output of 5rows x 2columns
           print (subset)
       else:
           print ('Specified file is not found')
   else:
       print('Error: Give only csv file')
else:
   print ('The function is called by another program')