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Practical Data Wrangling

You're reading from   Practical Data Wrangling Expert techniques for transforming your raw data into a valuable source for analytics

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Product type Paperback
Published in Nov 2017
Publisher Packt
ISBN-13 9781787286139
Length 204 pages
Edition 1st Edition
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Author (1):
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Allan Visochek Allan Visochek
Author Profile Icon Allan Visochek
Allan Visochek
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Table of Contents (10) Chapters Close

Preface 1. Programming with Data FREE CHAPTER 2. Introduction to Programming in Python 3. Reading, Exploring, and Modifying Data - Part I 4. Reading, Exploring, and Modifying Data - Part II 5. Manipulating Text Data - An Introduction to Regular Expressions 6. Cleaning Numerical Data - An Introduction to R and RStudio 7. Simplifying Data Manipulation with dplyr 8. Getting Data from the Web 9. Working with Large Datasets

Looking for patterns


Creating a good regular expression is a bit of a design process. A regular expression that is too rigid may not be able to match all of the potentially correct matches. On the other hand, a regular expression that is not specific enough may match a large number of strings incorrectly.

The key is to look for a well-defined pattern in the data that easily distinguishes the correct matches from otherwise incorrect matches. It is usually a helpful first step to look through the data itself. This allows you to get an intuitive sense for the existence and frequency of certain patterns.

The following python script uses pandas to read the dataset into a pandas dataframe, extract the address column, and print out a random sample of 100 addresses using the pandas series.sample() function. A random seed of 0 is used in order to make the resulting printout consistent. The script is available in the external resources as available in the external resources as explore_addresses.py.

import...
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