As a senior data scientist, I often encounter aspiring data scientists eager to learn about machine learning (ML). It’s a fascinating field that can seem daunting at first, but I assure you, with the right mindset and resources, anyone can master it. In this comprehensive guide, I will demystify machine learning, breaking it down into digestible concepts for beginners.
What is Machine Learning?
Machine learning is a subfield of artificial intelligence (AI) that enables computers to learn and make decisions or predictions without explicit programming. It involves feeding data to algorithms, which then generalize patterns and make inferences about unseen data.
There are three main types of machine learning: supervised learning, unsupervised learning, and reinforcement learning.
- Supervised Learning
In supervised learning, the algorithm is trained on a labelled dataset containing input-output pairs. The goal is to learn a mapping between the inputs and the corresponding outputs. Common supervised learning tasks include classification (e.g., spam vs. non-spam emails) and regression (e.g., predicting house prices).
- Unsupervised Learning
In unsupervised learning, the algorithm is fed an unlabelled dataset, and it attempts to discover hidden patterns or structures within the data. Typical unsupervised learning tasks include clustering (e.g., grouping customers based on their behaviour) and dimensionality reduction (e.g., reducing the number of features in a dataset to improve efficiency).
- Reinforcement Learning
Reinforcement learning algorithms learn by interacting with an environment and receiving feedback in the form of rewards or penalties. The goal is to learn a policy that maximises the cumulative reward over time. Reinforcement learning is commonly used in robotics, game playing, and recommendation systems.
The ML Process
The machine learning process typically consists of the following steps:
- Data Collection
Gathering relevant data is the first step in the machine learning process. Data can be collected from various sources such as databases, APIs, web scraping, or sensors. It is crucial to obtain high-quality data, as the performance of machine learning algorithms largely depends on the data used for training.
- Data Preprocessing
Data preprocessing involves cleaning and transforming raw data into a format suitable for machine learning algorithms. This step may include handling missing values, outlier detection, feature scaling, encoding categorical variables, and feature engineering.
- Model Selection
Choosing the right algorithm for the task at hand is critical. There are numerous machine learning algorithms, each with its strengths and weaknesses. Factors to consider when selecting a model include the problem type, the size and nature of the dataset, and the desired model complexity.
- Model Training
Model training involves feeding the preprocessed data to the chosen algorithm, which learns patterns from the data. In supervised learning, the model adjusts its internal parameters to minimise the difference between its predictions and the actual outputs.
- Model Evaluation
Evaluating the model’s performance on unseen data is crucial to ensure it generalises well to new examples. Common evaluation metrics include accuracy, precision, recall, F1-score, and mean squared error (MSE), depending on the problem type.
- Model Deployment
Once a satisfactory model has been trained and evaluated, it can be deployed in a production environment to make real-time predictions on new data.
Popular Machine Learning Libraries and Tools
There are many tools and libraries available to simplify the machine learning process. Some popular ML libraries include:
Scikit-learn is a widely-used Python library for machine learning that provides simple and efficient tools for data preprocessing, model selection, training, and evaluation. It supports various supervised and unsupervised learning algorithms, as well as tools for model selection and hyperparameter tuning.
TensorFlow is an open-source library developed by Google for numerical computation and large-scale machine learning. It is particularly popular for deep learning, a subfield of machine learning that focuses on neural networks with many layers.
Keras is a high-level neural networks API, written in Python, and can run on top of TensorFlow, Microsoft Cognitive Toolkit, or Theano. It is designed to enable fast experimentation with deep learning models, and its user-friendly interface makes it ideal for beginners.
PyTorch is an open-source deep learning library developed by Facebook, which allows for dynamic computation graphs, making it more flexible and easier to debug than TensorFlow. It has gained popularity due to its simplicity, performance, and ease of use.
SAS Viya is a comprehensive software suite for data management, advanced analytics, and predictive modelling. It is one of the oldest and most widely used statistical software packages in various industries, including finance, healthcare, and retail. SAS offers an extensive library of machine learning algorithms and data preprocessing techniques, as well as a user-friendly interface that makes it accessible for both beginners and experienced data scientists. While SAS is not open-source like the other libraries mentioned, it remains a popular choice in organisations that prioritise stability, support, and scalability.
Bonus: Tips for Aspiring Data Scientists
As a beginner in machine learning, it’s essential to keep the following tips in mind:
Master the Basics
Start by learning fundamental concepts in statistics, linear algebra, calculus, and programming (preferably Python). This foundation will allow you to understand and implement machine learning algorithms more effectively.
Learn by Doing
Apply what you learn to real-world projects. Participate in online competitions like those on Kaggle or work on personal projects to gain practical experience.
Stay Curious and Keep Learning
Machine learning is a constantly evolving field. Stay up to date with the latest developments by reading research papers, attending conferences, and following experts in the field.
Network and Collaborate
Connect with other aspiring and experienced data scientists through online forums, meetups, and social media. Collaboration can lead to new insights and opportunities.
Be Patient and Persistent
Mastering machine learning takes time and dedication. Be prepared to face challenges and setbacks along the way. Keep pushing yourself, and remember that every failure is an opportunity to learn and grow.
Machine learning is an exciting and rapidly evolving field that has the potential to revolutionize various industries. By understanding the basics, getting hands-on experience, using popular ML libraries, and staying curious, aspiring data scientists can unlock the power of machine learning to solve complex real-world problems.
Download the latest eBook on MLOps: “ModelOps Explained: A Starter’s Guide to Deploying and Managing AI and Analytical Models”
Article by Iain Brown, Head of Data Science @ SAS | LinkedIn
