Question

Python

I am creating a program that allows a user to extract data from a .csv file and print the statistics of a certain column in that file. The statistics include Count, Mean, Standard Deviation, Min, and Max. Here is the code I have so far:

import csv
import json

class POP:
""" Extract the data """
def __init__(self, line):
self.data = line
# get elements
self.id = self.data[0].strip()
self.geography = self.data[1].strip()
self.targetGeoId = self.data[2].strip()
self.targetGeoId2 = self.data[3].strip()
self.popApr1 = self.data[4].strip()
self.popJul1 = self.data[5].strip()
self.changePop = self.data[6].strip()

population = list()
with open('PopChange.csv', 'r') as p:
reader = csv.reader(p)
next(reader)
for line in reader:
population.append(POP(line))
population.append(POP(line))

obj = POP(line)
print(obj.popApr1)

As seen above, I am trying to print out the Count, Mean, Standard Deviation, Min, and Max of the column "popApr1", which is a column in the file. When I tried to print using print(obj.popApr1), it did not work. I believe that this action can be done using the .describe() method, but I am unsure of the syntax.

Answer 1

Solution:

1. import the statistics module
2. read the CSV file
3. create POP objects for each line
4. place the obj.popApr1 value from each line in a list
5. use python standard library method len(), min(), max() to get count, min and max for the list created above
6. use statistics module's method mean() and stdev to get the value of mean and standard deviation for the list created above

Code (PLEASE REFER THE SCREENNSHOT FOR INDENTATION OF THE PYTHON SCRIPT):

import csv
""" import statistics module to calculate mean and standard deviation """
import statistics

class POP:
""" Extract the data """
def __init__(self, line):
self.data = line
# get elements
self.id = self.data[0].strip()
self.geography = self.data[1].strip()
self.targetGeoId = self.data[2].strip()
self.targetGeoId2 = self.data[3].strip()
self.popApr1 = self.data[4].strip()
self.popJul1 = self.data[5].strip()
self.changePop = self.data[6].strip()

population = []
""" list to store popApr1 column value """
popApr1List = []
with open('PopChange.csv', 'r') as p:
reader = csv.reader(p)
next(reader)
for line in reader:
population.append(POP(line))
population.append(POP(line))

obj = POP(line)
""" append the value of obj.popApr1 to list """
popApr1List.append(float(obj.popApr1))

""" print count by getting length of list """
print ("Count: ", len(popApr1List))

""" print mean using statistics module's mean method """
print ("Mean: ", statistics.mean(popApr1List))

""" print min and max using python standard library methods """
print("Max: ", max(popApr1List))
print("Min: ", min(popApr1List))

""" print standard deviation using statistics module's stdev method """
print("Standard Deviation: ", statistics.stdev(popApr1List))

Input file used for testing:

Output: