In this tutorial, we will explore the world of Machine Learning (ML). ML is a subfield of artificial intelligence that provides systems the ability to learn and improve from experience without being explicitly programmed. You will learn the basic concepts and terminologies used in the field, and see how these techniques are used in real-world applications.
By the end of this tutorial, you will be able to:
Prerequisites:
Machine Learning is about building programs with tunable parameters (typically an array of floating point values) that are adjusted automatically so as to improve their behavior by adapting to previously seen data.
Let's delve into the details:
There are three major types of Machine Learning:
Supervised Learning - The program is “trained” on a pre-defined set of “training examples”, which then facilitate its ability to reach an accurate conclusion when given new data.
Unsupervised Learning - The program is given a bunch of data and must find patterns and relationships therein.
Reinforcement Learning - The algorithm learns to perform an action from experience.
Every machine learning algorithm has three components:
Representation - A way to represent knowledge. Examples: decision trees, sets of rules, instances, graphical models, neural networks, support vector machines, model ensembles and others.
Evaluation - A way to evaluate candidate programs (hypotheses). Examples: accuracy, prediction and recall, squared error, likelihood, posterior probability, cost, margin, entropy k-L divergence and others.
Optimization - A way to generate candidate programs. Examples: combinatorial optimization, convex optimization, constrained optimization.
We will use Python's Scikit-Learn library to demonstrate a simple example of supervised learning using a decision tree.
# Import necessary libraries
from sklearn.datasets import load_iris
from sklearn.model_selection import train_test_split
from sklearn.tree import DecisionTreeClassifier
# Load iris dataset
iris = load_iris()
# Split dataset into training set and test set
X_train, X_test, y_train, y_test = train_test_split(iris.data, iris.target, test_size=0.3)
# Create Decision Tree classifer object
clf = DecisionTreeClassifier()
# Train Decision Tree Classifer
clf = clf.fit(X_train,y_train)
# Predict the response for test dataset
y_pred = clf.predict(X_test)
This example demonstrates the process of a basic supervised learning task:
In this tutorial, we have introduced the concept of Machine Learning, its types and components. We have also seen a simple example of a supervised learning task using Python's Scikit-learn library.
To dive deeper into Machine Learning, you can explore the following resources:
Exercise 1: Load a different dataset from Scikit-learn and split it into a training set and a test set.
Exercise 2: Train a different classifier (e.g., K-Nearest Neighbors, Support Vector Machines) on the same dataset.
Exercise 3: Evaluate the performance of your classifier (e.g., accuracy, confusion matrix).
Review the Scikit-learn documentation to learn about different classifiers and evaluation metrics. Remember, the best way to learn is by doing! Happy coding!