chapter11.py

#!/usr/bin/env python

# Chapter 11 Assignment: Extracting Data With Regular Expressions

# Finding Numbers in a Haystack

# In this assignment you will read through and parse a file with text and
# numbers. You will extract all the numbers in the file and compute the sum of
# the numbers.

# Data Files
# We provide two files for this assignment. One is a sample file where we give
# you the sum for your testing and the other is the actual data you need to
# process for the assignment.

# Sample data: http://python-data.dr-chuck.net/regex_sum_42.txt
# (There are 87 values with a sum=445822)
# Actual data: http://python-data.dr-chuck.net/regex_sum_201873.txt
# (There are 96 values and the sum ends with 156)

# These links open in a new window. Make sure to save the file into the same
# folder as you will be writing your Python program. Note: Each student will
# have a distinct data file for the assignment - so only use your own data file
# for analysis.

# Data Format
# The file contains much of the text from the introduction of the textbook
# except that random numbers are inserted throughout the text. Here is a sample
# of the output you might see:

'''
Why should you learn to write programs? 7746
12 1929 8827
Writing programs (or programming) is a very creative
7 and rewarding activity.  You can write programs for
many reasons, ranging from making your living to solving
8837 a difficult data analysis problem to having fun to helping 128
someone else solve a problem.  This book assumes that
everyone needs to know how to program ...
'''

# The sum for the sample text above is 27486. The numbers can appear anywhere
# in the line. There can be any number of numbers in each line (including none).

# Handling The Data
# The basic outline of this problem is to read the file, look for integers using
# the re.findall(), looking for a regular expression of '[0-9]+' and then
# converting the extracted strings to integers and summing up the integers.

import re

file = open('regex_sum_201873.txt', 'r')

sum = 0

for line in file:
    numbers = re.findall('[0-9]+', line)
    for number in numbers:
        sum = sum + int(number)

print(sum)