DEV Community: Wairimu Becky

Getting Started With Excel For Data Analytics: From Basics To Data Cleaning

Wairimu Becky — Sun, 30 Aug 2026 11:01:28 +0000

It’s week 3 in my Data Analytics class. We’ve finally finished installing our essentials, learnt how to successfully push projects to GitHub, and now we’re ready for Excel. We began with the basics of Excel, that is rows and columns, the ribbon and some of the functions of the tabs and commands. The next bit was data cleaning, and this is where it begins to get interesting, so let me take you with me step by step.
To make it simple, we will use a dataset to help explain how to clean data. Data is information, and the clearer and cleaner the data, the better the insights derived. The dataset, Dirty Café Sales, that we will use through this journey, has been obtained from Kraggle, by Ahmed Mohamed.
This is a copy of the original data set;

The first step is to save the file as an Excel Workbook file, and then create a copy of the raw data in the new sheet to work from;

Now we can begin to work on the cells themselves. The cells are the rectangular boxes you see on the workbook, intersections of rows and columns. It is represented/referenced by a column name and row number such as A2, F8.
We’ll autofit the column widths, freeze the top row pane, and edit the top row with headers so as to help us easily see what we’re working with.

This is what we’re now working with.

Let’s now work on the data itself. We begin by removing duplicates;

Next, we reset any inconsistent data types. We start by turning on the filters on the headers so that we can know what we’re working with in each column. There are columns with text values, other numerical values, others both. We will work methodically through the sheet from beginning to end.

We change all ‘ERROR’, ‘UNKNOWN’ or blank values to ‘Unknown’, and format the numerical cells to reflect the data they represent i.e currency;

We do this across the sheet.
Next, we learnt about conditional formatting. This is a kind of formatting that changes the appearance of cells.

At this point we got introduced to Text Functions, which are used to standardize text value, i.e if you want text in Proper case or UPPER case or all lower case, where you use the functions Proper(), UPPER() and lower() respectively. There are other like Trim() which you use to remove extra spaces, Len() which gives you the length of text among others. An interesting one is CONCAT() which you use to combine text in two cells, for example if you’re generating an email using first name and last name which are in different cells.

Our most recent class has been on sorting and filtering. You can sort data depending on the type i.e for text values, sort A-Z/Z-A, for numeric values, sort smallest-largest/largest-smallest, for dates, sort oldest-newest/newest-oldest.
You can also do a multi-level sort where you sort across different criteria. For example, below, I decided to sort according to the following selections;

Next comes the math part. I was surprised by how easy Excel made mathematical functions. We’ll begin with aggregate functions that process a range of rows and give a single summarized value. I’ll list them below along with their functions;
Power()- exponent, raises to a specified power
Product()- multiplication of values in a range
Sum()- Sum of values in range
Average()- average of values in range
Median()- value at the center of all values in range
Mode()- most repetitive of values in range
Min()- lowest value
Max()- highest value
SQRT()- square root

Then we have statistical functions;
Count()- counts only cells with numeric values
Counta()- count all non-blank cells
Countblank()- counts only blanks

We also have conditional aggregation that applies aggregate functions to only cells that meet specified criteria e.g Countif();

Finally, we learnt about the functions used to retrieve date values i.e;
Today()- brings you today’s date
Now()- today’s date + current time
Year()
Month()
Day()
Datedif()- gives the difference between two dates
Networkdays()- gives the difference between 2 dates excluding weekends

That’s all for today in Excel world folks. Till next time…

My-First-Github-Project: From Installation To Execution

Wairimu Becky — Sun, 23 Aug 2026 17:37:30 +0000

Introduction

My first week studying Data Science and Analytics involved an initiation to Git. Before then, I had only encountered GitHub as a place where developers stored code, but I had not really understood what was actually happening.
In this article, I take you on the journey of my first experience with Git, taking a project from a folder on my pc, and pushing it to a GitHub repository using Git and SSH. We will cover installation and configuration, how Git works, the creation and authentication of an SSH key, creation of a GitHub repository, and finally, pushing a project to GitHub.

Git, GitHub and SSH

Git

Git is a version control system. This means that it helps you keep track of your ongoing projects in a variety of ways. You can save versions of your project, retrieve older versions, create separate branches of your work, and even merge different people's work together. It's saved in your pc so you can also work offline.

GitHub

GitHub is a platform that lets you store and collaborate on Git projects online. As Git manages the version history of a project, GitHub provides an online location where that repository can be stored and shared.

SSH Keys

The word SSH in full stands for secure shell. This is a protocol that is used to establish secure communication between computers over a network. Instead of having to enter your username and password constantly, the key provides a secure method of authenticating your computer with GitHub.
The key itself is comprised of a pair that is the private and public key. The private key is private, as the name suggests, stays on your pc and should never be shared with anyone. The public corresponding key is what goes in your GitHub account.

Installation

The first step was to create a GitHub account and install Git Bash on my computer. Git Bash is a command-line environment on Windows which executes Git commands. This was my first introduction to the fact that development tasks can be performed directly through a terminal.

Configuring Git

The next step was configuration. Git needs to know who is using it, so I configured my username and email address using;
git config --global user.name "Wairimu Becky"
git config --global user.email "beckywairimu@gmail.com"
I checked whether the configuration was successful using:
git config --list
I also configured the default branch name to "main";
git config --global init.defaultBranch main
A branch is a line of development inside a repository.

Generating an SSH Key

I generated the key using:

The terminal then prompted me to choose where to save the key and whether to create a passphrase. The file ending in .pub is the public key, while the corresponding file without .pub is the private key.
After generating, I copied the public key to my GitHub account, under the SSH and GPG key section.

Authentication

After adding the public key and verifying using email, the next step was to test whether the SSH connection was successful using;

How Git works

There are some different processes involved when using Git;

Working directory

This is the project folder where I create and edit files. When I make a change, Git detects that the file has been changed, but the change has not yet been prepared for a commit.
After making sure I was in the right folder using;
cd Desktop,
I began by creating these folders using;
mkdir my-first-GitHub-project
mkdir data
mkdir notebooks
mkdir scripts
touch README.md
touch analysis.py
Then, I input some text into the readme file using;
nano README.md

Staging

This is the process of selecting the changes I want to include in the next commit using:
git add . (The dot represents the current directory)
You can check which files have not yet been tracked, or have been modified, or staged using:
git status

Commits

A commit is a record of a checkpoint in the project's history. It should clearly describe what has been added/changed.
Once the files I have chosen are staged, they can be recorded in a commit:
git commit -m "Add Analysis Project"
Now the project is a Git repository on my computer. We've still not yet uploaded to GitHub.

GitHub Repository

The purpose of this repository is to become the remote location connected to my existing local repository. Next, is to tell Git the location of the remote repository. Once I created a GitHub repository, I used the link provided under SSH connection in Git;
git remote add origin (paste the link here)
The connection can be checked using;
git remote -v

Push

Now, it's time to push the project existing locally to GitHub using;
git push -u origin main
After running the command successfully, I refreshed the GitHub repository page and saw the project files that I had created on my pc.

In Conclusion

What I learned from this process, is that Git is what tracks and manages the history of a project, while GitHub is the online platform for hosting and collaborating on that project. SSH provides secure authentication between my pc and GitHub.
As someone beginning a journey in Data Science and Analytics, learning Git is clearly a very useful technical skill. While my first GitHub push may have been a relatively small achievement, it introduced me to a space that will evolve far beyond this first project.

Dipping My Toe In The Cold, Blue TechWorld...

Wairimu Becky — Sun, 16 Aug 2026 18:04:55 +0000

Hello World

I've been interested in the world of technology for a very long time. Although I have to admit, like many others, I was also a little scared. It all seems like a different dimension of 0's and 1's. In this short review, I will tell you about my first week at LuxDevHq Academy, studying Data Engineering and Data Analysis.

On-Boarding at Lux

Day one started with a short class on markdown lingo, for the very purpose of writing this article, as I am now. It was relatively easy to comprehend, and practicing with it has been kind of fun.

And then we began the journey downhill

If I left day 1 feeling good and mildly confident, day 2,3 and 4 just smashed me. We were being guided to install some of the apps we will be using for the duration of our course. These include postgresql, dbeaver, gitbash, Power BI, just to name a few. Although setting up connections to the online servers was abit hectic, it was still do-able. I started seeing stars when it was time to connect my github and gitbash accounts. Creating an SSH Key?
This was me the entire time...

Eventually, the Sun shone again

Despite the heavy challenges (and believe me they were heavy) that were associated with this process, we persevered and emerged victorious in the end. Along that brief journey I discovered that my course mates are hilarious, and that we all have what it takes to see it through to the end.
Yes, I was finally able to create a ssh key. We also have incredible instructors. And it doesn't seem so hard now but then!

Dear Tech World, to me you seem a huge, formidable ocean. And I plan to swim your entirety. So, this is me, buckling up for the ride.
How was your first experience in the tech world like?