Python Tutorial
Plotly Getting Started
Install Plotly and draw a figure with Plotly Express. fig.show() opens it in the browser.
Install
python -m pip install plotly pandasFirst Chart
import plotly.express as px
df = px.data.iris()
fig = px.scatter(df, x="sepal_width", y="sepal_length", color="species")
fig.show()px.data.iris() is a built-in sample table. Replace it with your own DataFrame when you are ready.
📘 Real-World Deep Dive
Knowing <strong>Plotly Getting Started (Plotly)</strong> well is what turns Plotly from a curiosity into a daily tool — you'll reach for it in nearly every real project.
Real-Life Scenario
An end-to-end usage of Plotly Getting Started that you'd actually see in a data pipeline or analytics notebook.
Real-Life Example
import plotly.express as px
df = px.data.gapminder().query("year == 2007")
fig = px.scatter(df, x="gdpPercap", y="lifeExp", size="pop", color="continent",
hover_name="country", log_x=True, size_max=60)
fig.show()Expected Output
(no output)Common mistakes
- Plotly Express (
px) is concise but auto-layouts aggressively — switch to Graph Objects (go) for full control. - Passing a list with mixed types to
px.linetriggers silent upcasting; convert first to typed arrays. - Plotly expects millisecond timestamps for time axes (
df["date"].astype("datetime64[ms]")). - Treating Plotly Getting Started as a black box without reading the docs — the API has subtle defaults that bite when you scale.
🚀 Performance & Best Practices
- For large plots use
Scattergl(WebGL) instead ofScatter. - In Dash apps, send data with
dcc.Store+json.dumpsrather than re-passing Python objects. - Disable
uirevisionwhen you want Plotly to fully redraw instead of preserving state. - When working with Plotly, prefer vectorised / batched operations over Python loops.
🧪 Try It Yourself
- Reproduce the snippet on a representative slice of your own data.
- Profile the snippet with
cProfileortimeitand find the single biggest improvement. - Generalise the snippet into a small, reusable function you can drop into future projects.