Matplotlib Fundamentals

Matplotlib is the foundational plotting library in Python. Nearly every other Python visualisation library (Seaborn, Pandas plotting, even some Plotly features) is built on top of or integrates with Matplotlib. Understanding its architecture gives you complete control over every element of a chart.

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Installation

pip install matplotlib

The standard import convention:

import matplotlib.pyplot as plt
import numpy as np

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The Two Interfaces

Matplotlib offers two ways to create plots:

1. Pyplot Interface (Quick and Simple)

import matplotlib.pyplot as plt

plt.plot([1, 2, 3, 4], [10, 20, 25, 30])
plt.xlabel("X Axis")
plt.ylabel("Y Axis")
plt.title("Simple Line Plot")
plt.show()

2. Object-Oriented Interface (Recommended)

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
ax.plot([1, 2, 3, 4], [10, 20, 25, 30])
ax.set_xlabel("X Axis")
ax.set_ylabel("Y Axis")
ax.set_title("Simple Line Plot")
plt.show()

Tip: Always use the object-oriented interface (fig, ax = plt.subplots()) for anything beyond the simplest plot. It gives you explicit control over figures and axes.

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Figure and Axes — The Core Concepts