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How to Build Your First Machine Learning Model from Scratch

machine learning models


Have you ever wondered how machines can recognize faces, understand speech, or identify spam? The magic behind these intelligent applications lies in machine learning models. With some basic coding skills and publicly available data, you can train models to automate tasks, find patterns, and make predictions too. 

Whether you’re a programmer looking to expand your skills or simply ML curious, building your first model from the ground up is an exciting way to obtain hands-on machine learning knowledge.  Who knows, your first ML project could even evolve into the next big AI innovation! Let’s get started.

Understanding the Basics

Before diving in, let us build intuition for how machine learning models work. 

1. Feed data to the model 

2. Model learns patterns and relationships in the data

3. New data is fed to the trained model

4. Model uses learned patterns to make predictions or decisions about new data

For example, to create a model that predicts home prices, you would provide historical data on home sales prices and characteristics like size, location, etc. 

The model would learn associations between the characteristics and sales prices. Then when given data on a new home, it applies those learnings to predict the home’s value.

The quality of the model’s predictions depends heavily on the data used to train it. Real-world data that is large, clean, and relevant will produce better results. 

As the model processes more data, its accuracy improves. Once trained, models can make predictions very quickly using what they’ve learned.

Setting Up Your Environment 

To build models, you need programming tools suited for machine learning. Popular options include:


A prime selection for machine learning is owing to its rich array of data science libraries, such as Pandas, NumPy, and sci-kit-learn. This open-source platform not only offers a cost-effective solution but also welcomes beginners with open arms.

A statistical programming language with ML packages like Caret and tidy models. Has extensive tools for data analysis.


Proprietary software with a large ML toolbox and interface for technical computing. 

Azure Machine Learning

A cloud platform to develop and deploy ML models. Includes datasets and notebooks.

Amazon SageMaker 

A fully managed cloud service to build, train, and deploy ML models. Integrates with AWS services.

Select the one you feel at ease. Install any required packages, libraries, or tools to get your environment set up for hands-on ML modelling.

Gathering and Preparing Data 

Machine learning models require a training dataset to learn from. As a beginner, you can find many open datasets online to experiment with. For real-world problems, you’ll need quality, relevant data collected specific to your use case. 

Your data should include:

Features – The input variables or attributes that will be used to make predictions. Such as a home’s size, location, # bedrooms, etc.

Target variable – The output you are trying to predict. Such as the home’s sales price.

Before training a model, the data often needs preparation through:

– Importing into your workspace

– Cleaning missing, incorrect or duplicate values

– Converting text categories to numbers

– Splitting data into training and test sets

Thoroughly exploring and preprocessing the data is an important step. It directly affects model performance.

Selecting a Machine Learning Algorithm

Many types of ML algorithms exist. Choosing the right one depends on your data type, size, and project goals. Common algorithms for beginners include:

Linear Regression – Predicts continuous values like sales figures. Simple but powerful baseline model.

Logistic Regression – Predicts binary outcomes like pass/fail or spam/not spam. Popular for classification tasks.  

Random Forest – Decision tree ensemble method resistant to overfitting. Works well for both classification and regression problems.

K-Nearest Neighbors – Classification algorithm that looks at “nearest” examples. Simple and intuitive approach.

Neural Networks – Models inspired by human neurons. Excellent for complex problems like image recognition with large datasets. Requires more tuning.

Experiment with a few algorithms to discover what works best for your project goals and data patterns.

Building the Model

We’ve covered the basics – now let’s build our first model using sample code:

1. Import ML packages and load data into a data frame

2. Separate features from the target variable 

3. Split data into training and test sets (e.g. 80% training, 20% test)

4. Initialize the model object (e.g. LinearRegression()) 

5. Train the model on the training data using .fit()

6. Make predictions on the test data using .predict()

7. Compare predictions to true test values to evaluate performance

Following these steps will produce your first working ML model! But don’t expect high accuracy just yet – more refinement is needed.

Training and Evaluation

Initially, the model will perform poorly since it hasn’t learned the patterns yet. Training occurs when the model iterates through the data, gradually improving its predictions over many rounds. We evaluate models using the test set kept separate from training. Key metrics include:

– Accuracy – % of overall correct predictions

– Precision – Of positive predictions, how many were correct

– Recall – Of actual positives, how many did the model correctly predict  

Analyzing these metrics guides the next steps of improving model performance.

Fine-tuning and Optimization

Based on the initial evaluation, we fine-tune models to enhance accuracy:

– Try different algorithms and parameters – Every model has options to adjust

– Engineer new features – Combine or transform features to uncover insights

– Clean more data issues – Garbage in = garbage out

– Gather more quality training data – More real-world examples improve learning

– Try ensemble methods – Combine multiple models for the best parts of each

Experimentation is key to getting the most out of your data. Patience leads to better machine learning.

Making Predictions

Once you have developed a machine learning model that performs well during training and testing, the next step is to use it to make predictions on new, real-world data. 

This process of applying a trained model to make decisions or forecasts is known as model deployment.

To deploy a model into production, you first need to integrate it into an application, system, or process where it can receive input data, apply its learned logic, and return predictions. 

For example, you may add API endpoints that allow your model to receive data, run predictions, and send back results to other apps or databases. Or you could package the model into a web application, Excel plugin, or other executable program. 

Before relying on its predictions, you should first evaluate model performance on fresh, real-world examples that differ from your original training data. 

Monitor the accuracy, precision, recall, or other relevant metrics to confirm it generalizes well. If performance dips, further fine-tuning may be required before full deployment.

Once deployed, it’s important to keep monitoring how the model performs on live data. 

Many factors like changing environments and data drift can cause model accuracy to degrade slowly over time. You can detect deterioration by periodically evaluating predictions against true outcomes. 

To maintain reliability, models should be retrained on new data regularly – say weekly or monthly depending on the use case. Retraining allows the model to incrementally learn from the most recent examples. You can automate this replenishment using pipelines.

Congratulations, you’ve built a machine-learning model from scratch! With more practice, you’ll be ready to create ML solutions that solve important problems and expand possibilities. Share in the comments how and where you’d implement machine learning in your everyday life!

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