Matplotlib Tutorial
matplotlib is Python's foundational charting library. Most other plot tools (seaborn, plotnine, pandas .plot()) wrap it.
Install
SHELL
pip install matplotlib
Your first chart
PYTHON
import matplotlib.pyplot as plt
x = [1, 2, 3, 4, 5]
y = [1, 4, 9, 16, 25]
plt.plot(x, y)
plt.title('y = x²')
plt.xlabel('x'); plt.ylabel('y')
plt.show()
Common chart types
| Function | Draws |
|---|---|
plt.plot | Line. |
plt.scatter | Scatter plot. |
plt.bar / plt.barh | Bars. |
plt.hist | Histogram. |
plt.pie | Pie chart. |
plt.imshow | Image / heatmap. |
Subplots
PYTHON
fig, axes = plt.subplots(1, 2, figsize=(10, 4))
axes[0].plot(x, y)
axes[1].bar(['a', 'b', 'c'], [3, 1, 4])
fig.suptitle('Two charts side by side')
plt.show()
Save to a file
PYTHON
plt.savefig('chart.png', dpi=150, bbox_inches='tight')
The pyplot vs OO style
- pyplot — quick and stateful:
plt.plot,plt.title,plt.show. Like MATLAB. - Object-oriented — explicit Figure / Axes references:
ax.plot,ax.set_title. Better for complex charts and reusable code.
Tip: For statistical plots,
seaborn (built on matplotlib) is much higher level. For interactive dashboards, plotly outputs HTML/JS.Example
Example
# import matplotlib.pyplot as plt
# plt.plot([1, 2, 3], [1, 4, 9])
# plt.show()
print('matplotlib draws charts.')
Try it Yourself »
Exercise
Display the figure.
plt.
()
Four letters.
Discussion
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