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Data Visualization with Plotly: Essential Chart Types Explained

Plotly is a powerful Python library for creating interactive, publication-quality visualizations. Here's a concise guide to its main chart types with examples:

Basic Charts

1. Scatter Plots

Purpose: Show relationships between two continuous variables
Best for: Correlation analysis, clusters, outliers

import plotly.express as px
df = px.data.iris()
fig = px.scatter(df, x="sepal_width", y="sepal_length", color="species")
fig.show()

2. Line Charts

Purpose: Display trends over time/ordered categories
Best for: Time series, progress tracking

df = px.data.stocks()
fig = px.line(df, x="date", y="GOOG", title="Google Stock Price")
fig.show()

3. Bar Charts

Purpose: Compare quantities across categories
Best for: Performance comparison, survey results

df = px.data.tips()
fig = px.bar(df, x="day", y="total_bill", color="sex")
fig.show()

4. Pie Charts

Purpose: Show proportional composition
Best for: Market share, budget allocation

df = px.data.tips()
fig = px.pie(df, names="day", values="total_bill")
fig.show()

Statistical Charts

5. Histograms

Purpose: Display data distribution
Best for: Understanding spread, skewness

fig = px.histogram(df, x="total_bill", nbins=20)
fig.show()

6. Box Plots

Purpose: Show quartiles and outliers
Best for: Statistical comparison, outlier detection

fig = px.box(df, x="day", y="total_bill", color="smoker")
fig.show()

7. Violin Plots

Purpose: Combine box plot with density estimation
Best for: Distribution shape comparison

fig = px.violin(df, x="day", y="total_bill", box=True)
fig.show()

Advanced Visualizations

8. Heatmaps

Purpose: Visualize matrix data with colors
Best for: Correlation matrices, confusion matrices

fig = px.imshow([[1, 20, 30], [20, 1, 60], [30, 60, 1]])
fig.show()

9. 3D Scatter Plots

Purpose: Explore 3-variable relationships
Best for: Multidimensional data analysis

fig = px.scatter_3d(df, x='sepal_length', y='sepal_width', z='petal_width')
fig.show()

10. Maps (Choropleth)

Purpose: Geographic data visualization
Best for: Regional comparisons, election results

df = px.data.gapminder().query("year == 2007")
fig = px.choropleth(df, locations="iso_alpha", color="gdpPercap")
fig.show()

Financial Charts

11. Candlestick Charts

Purpose: Show financial market data
Best for: Stock price movements

df = px.data.stocks(indexed=True)
fig = px.line(df, facet_col="company", facet_col_wrap=2)
fig.show()

Interactive Features

Plotly charts automatically include: - Hover tooltips - Zoom/pan controls - Click legend to toggle traces - Download as image option

To customize:

fig.update_layout(
    title="Custom Title",
    xaxis_title="X Label",
    yaxis_title="Y Label"
)

For Jupyter notebooks, ensure you have the required renderer:

import plotly.io as pio
pio.renderers.default = "notebook"

Plotly excels at creating interactive visualizations that can be embedded in web applications (using Dash) or exported as standalone HTML files. The library offers over 40 chart types with extensive customization options while maintaining simplicity through its Plotly Express high-level API.