Plotting in Python

Data visualization is essential for interpreting and presenting data. In Python, several libraries can be used for plotting, with Matplotlib and Seaborn being among the most popular. This tutorial covers key libraries, plotting functions, customization, and different types of plots.

1. Top Plotting Libraries

Here are some of the most widely used libraries for plotting in Python:

• Matplotlib: The foundational library for creating static, interactive, and animated visualizations in Python. It provides extensive control over the appearance of plots.
• Seaborn: Built on top of Matplotlib, Seaborn provides a high-level interface for drawing attractive statistical graphics.
• Plotly: Known for interactive and dynamic plots, Plotly is great for creating interactive web-based visualizations.
• Bokeh: Another interactive plotting library that allows for creating web-ready plots with complex interactions.

2. Basic Plotting with Matplotlib

Matplotlib is a powerful library for creating static plots. Here's how to use it for basic plotting:

2.1 Installing Matplotlib

pip install matplotlib

2.2 Basic Plot

Creating a simple line plot:

import matplotlib.pyplot as plt

# Basic Line Plot
x = [1, 2, 3, 4, 5]
y = [2, 3, 5, 7, 11]
plt.plot(x, y)

# Customize Plot
plt.title('Basic Line Plot')
plt.xlabel('X-axis Label')
plt.ylabel('Y-axis Label')
plt.xticks([1, 2, 3, 4, 5])
plt.yticks([2, 3, 5, 7, 11])

plt.show()

3. Advanced Plotting with Seaborn

Seaborn simplifies many common tasks and produces attractive statistical plots:

3.1 Installing Seaborn

pip install seaborn

3.2 Boxplot Example

Creating a boxplot to visualize the distribution of data:

import seaborn as sns
import pandas as pd

# Sample DataFrame
data = pd.DataFrame({
    'Category': ['A', 'B', 'C', 'A', 'B', 'C'],
    'Values': [10, 20, 15, 30, 25, 35]
})

# Boxplot
sns.boxplot(x='Category', y='Values', data=data)
plt.title('Boxplot Example')
plt.show()

4. Interactive Plotting with Plotly

Plotly allows for interactive plots that can be embedded in web applications:

4.1 Installing Plotly

pip install plotly

4.2 Creating an Interactive Plot

Example of a simple interactive line plot:

import plotly.graph_objects as go

# Create a figure
fig = go.Figure()

# Add a trace (line plot)
fig.add_trace(go.Scatter(x=[1, 2, 3, 4, 5], y=[2, 3, 5, 7, 11], mode='lines+markers'))

# Update layout
fig.update_layout(title='Interactive Line Plot', xaxis_title='X-axis', yaxis_title='Y-axis')

fig.show()

5. Creating Multiple Subplots

You can create multiple subplots within a single figure using Matplotlib:

5.1 Example with Four Subplots

Creating a 2x2 grid of plots:

import matplotlib.pyplot as plt

# Create subplots
fig, axs = plt.subplots(2, 2, figsize=(10, 8))

# Plot in each subplot
axs[0, 0].plot([1, 2, 3], [4, 5, 6], 'tab:blue')
axs[0, 0].set_title('Plot 1')

axs[0, 1].bar(['A', 'B', 'C'], [10, 20, 15], color='tab:orange')
axs[0, 1].set_title('Plot 2')

axs[1, 0].hist([1, 2, 1, 2, 3, 4], bins=5, color='tab:green')
axs[1, 0].set_title('Plot 3')

axs[1, 1].scatter([1, 2, 3], [4, 5, 6], color='tab:red')
axs[1, 1].set_title('Plot 4')

# Adjust layout
plt.tight_layout()
plt.show()

6. Adding Legends

Legends are useful for identifying different datasets or categories in a plot:

6.1 Example with Legends

Adding legends to a line plot:

import matplotlib.pyplot as plt

# Plot with legend
plt.plot([1, 2, 3, 4], [10, 15, 13, 17], label='Data 1')
plt.plot([1, 2, 3, 4], [7, 14, 12, 18], label='Data 2')
plt.legend()

# Customize plot
plt.title('Line Plot with Legends')
plt.xlabel('X-axis Label')
plt.ylabel('Y-axis Label')

plt.show()