What is Data Wrangling? An Introduction - HackerRank Blog

In a world increasingly shaped by vast quantities of data, the field of data science has never been more crucial. From small startups to global corporations, organizations are leveraging data to drive decision-making, identify new opportunities, and gain a competitive edge. But these insights are only as good as the data that informs them. In order for organizations to harness the full potential of their data, they need it to be clean, accurate, and readily usable. And they need people with the skills to wrangle it. 

As the sheer volume of data has grown in recent years, the demand for skilled individuals with data wrangling capabilities has grown too. In fact, HackerRank’s 2023 Developer Skills Report found data wrangling to be the sixth most in-demand technical skill, growing by 405% year over year. 

Data wrangling is the bridge between raw data and the refined, structured information that businesses rely on to make informed decisions. In this post, we’ll explore the specific steps involved in the process, the techniques employed, and the tools and skills necessary to excel in this discipline.

Understanding Data Wrangling and Its Importance

Data wrangling is the process of cleaning, structuring, and enriching raw data into a desired format for better decision making and analysis. This process is a fundamental step in turning disjointed data into a valuable resource. 

The importance of data wrangling is evident when we consider the nature of data in its raw form. It’s often messy, incomplete, and inconsistent. For instance, consider a dataset of customer information where some entries might have missing values, inconsistent date formats, or typos in the customer names. Without proper cleaning and structuring, it’s nearly impossible to derive accurate insights. In essence, data wrangling is the necessary first step in the data science pipeline.

The benefits of data wrangling include:

• Data Quality and Accuracy: Inaccurate or low quality data can lead to incorrect conclusions. Data wrangling helps to mitigate this by cleaning and transforming data, ensuring that the final dataset is of the highest quality.
• Time Saving: While data wrangling might seem like a time-consuming process, it actually saves time in the long run. Clean, well-structured data is easier to interpret and less likely to cause issues during the analysis phase.
• Informed Decision Making: The ultimate goal of any data-driven organization is to make better business decisions. Data wrangling is key to achieving this, as it transforms data into a format that can be easily understood and analyzed, leading to more informed choices.

The Data Wrangling Process

The process of data wrangling can be broken down into several key steps, each of which plays a crucial role in transforming raw data into a clean and usable format.

1. Data Collection

Data collection is the first step in the data wrangling process. This involves gathering data from various sources, such as databases, CSV files, APIs, and more. The goal is to ensure that the data collected is relevant and comprehensive. Gathering data from different sources, including internal and external databases, social media platforms, and more, is a crucial part of this step. It’s also important to ensure that the data collected is relevant to the analysis or decision-making process at hand and that it is comprehensive enough to provide a complete picture.

2. Data Cleaning

Once the data is collected, the next step is to clean it. This involves handling missing values, correcting inconsistencies and errors, and more. Handling missing values can be done through various methods, such as imputation, deletion, or other context-dependent methods. Another crucial aspect of data cleaning is addressing and correcting inconsistencies and errors, such as fixing typos, standardizing date formats, and more.

3. Data Transformation

Data transformation involves converting data into a suitable format for analysis. This might include creating new variables or features that are more relevant to the analysis. Converting data into a suitable format can involve changing data types, normalizing data, and more. Additionally, creating new variables or features, such as creating a new column that represents the age of a customer based on their date of birth, can provide more relevant information for analysis.

4. Data Enrichment

Data enrichment involves merging data from different sources and adding new information to enhance the dataset. Combining data from different datasets can create a more comprehensive dataset that provides a fuller picture of the situation. Adding new information to the dataset, such as additional context or data, can also enhance the analysis.

5. Data Validation

The next step in the data wrangling process is to validate the data to ensure its accuracy and reliability. Ensuring accuracy and reliability involves checking the data against predefined criteria to verify its validity. 

Say, for example, you were analyzing a list of email addresses. Data validation checks you could use to test the data include:

• Format Validation: Ensure that the email address provided follows the correct format for an email address.
• Domain Validation: Check if the domain of the email address is a real and active domain by performing a DNS lookup on the domain.
• Blacklist Check: Check if the email address is on a blacklist of known disposable email services or known spammers.
• Length and Character Limit: Ensure the email address isn’t too long and doesn’t contain illegal characters.

6. Data Publishing

Once the data has been collected, cleaned, transformed, enriched, and validated, the final step is to publish it. This involves making the data available for analysis or reporting. Data publishing can take various forms, such as creating dashboards, reports, or other visualizations that make the data easy to understand and interpret. The goal is to ensure that the data is accessible and usable for decision-makers and other stakeholders.

Data Wrangling Techniques

Data wrangling involves employing a range of techniques to transform raw data into a usable format. These techniques include:

• Data Filtering involves sifting through data to remove any irrelevant or unnecessary information. This step is crucial as it ensures that the dataset only contains pertinent data, making the analysis process more straightforward and accurate.
• Data imputation is the process of replacing missing or null values with substitute values. This is important because missing data can lead to inaccurate analyses and biased results. There are several imputation methods available, such as mean imputation, where missing values are replaced with the mean value of the variable.
• Data encoding and decoding involve converting data from one form to another. For example, categorical data, which might include variables like color or gender, can be converted into numerical format to facilitate analysis. This step is essential, as most analysis methods require numerical input.
• Regular expressions are sequences of characters that are used as a search pattern. They can be used to extract information from text data, such as emails or phone numbers, or to find and replace specific patterns in a dataset. This technique is powerful for cleaning and organizing textual data.
• Data aggregation involves summarizing and grouping data to provide a more comprehensive view of a dataset. For example, data can be aggregated to calculate averages, sums, or counts. This technique is useful for identifying trends and patterns in a dataset, facilitating more informed decision-making.

Key Data Wrangling Skills

Data wrangling requires a unique set of skills and competencies to effectively transform raw data into a clean, usable format. Here are some of the key skills and competencies that are essential for successful data wrangling:

Technical Skills

• Programming: A strong grasp of programming languages such as Python or R is crucial, as these are often used for data wrangling tasks.
• Database Management: Familiarity with database management tools like SQL or MongoDB is important for querying and manipulating data.
• Data Visualization: Knowledge of data visualization tools such as Tableau or Power BI can be helpful for creating visual representations of data.
• Anomaly Detection: The ability to identify and address anomalies in data is an essential skill in ensuring the quality and accuracy of the dataset. This involves detecting outliers or unusual patterns that may indicate errors or other issues.

Analytical Skills

• Critical Thinking: The ability to think critically and ask the right questions is important for understanding the data and the context in which it will be used.
• Problem-Solving: Data wrangling often involves solving complex challenges, so strong problem-solving skills are essential.
• Attention to Detail: A keen eye for detail is necessary to spot errors and inconsistencies in the data.

Communication Skills

• Clear Communication: The ability to communicate clearly and effectively is important, as data wranglers often need to explain their findings to non-technical stakeholders.
• Data Storytelling: The ability to tell a story with data is crucial, as it helps to make the data more accessible and understandable.

Other Important Competencies

• Domain Knowledge: Understanding the specific industry or domain is important, as it helps to provide context for the data.
• Adaptability: The world of data is constantly evolving, so the ability to adapt to new tools and technologies is crucial.
• Collaboration: Data wrangling is often a collaborative process, so the ability to work effectively with others is important.

Preparing for a Data-Driven Future

The world is witnessing exponential growth in data, with an estimated 328.77 million terabytes of data being generated every day. This growing ecosystem of data presents tremendous opportunities for businesses to extract valuable insights and make informed decisions. However, it also highlights the growing need for skilled professionals who can wrangle this vast sea of data effectively.

To meet this need, businesses will need to simultaneously level up their tech hiring strategies and invest in upskilling their teams. Even as we begin to see greater integration of automated tools and artificial intelligence in the data wrangling process, the human element will remain indispensable. Investing in the development of data wrangling skills and tools has become necessary step to future-proof your organization. 

This article was written with the help of AI. Can you tell which parts?