gh-k-dense-ai-claude-scientific-skills-scientific-skills/skills/seaborn/references/objects_interface.md

Seaborn Objects Interface

The seaborn.objects interface provides a modern, declarative API for building visualizations through composition. This guide covers the complete objects interface introduced in seaborn 0.12+.

Core Concept

The objects interface separates what you want to show (data and mappings) from how to show it (marks, stats, and moves). Build plots by:

1. Creating a Plot object with data and aesthetic mappings
2. Adding layers with .add() combining marks and statistical transformations
3. Customizing with .scale(), .label(), .limit(), .theme(), etc.
4. Rendering with .show() or .save()

Basic Usage

from seaborn import objects as so
import pandas as pd

# Create plot with data and mappings
p = so.Plot(data=df, x='x_var', y='y_var')

# Add mark (visual representation)
p = p.add(so.Dot())

# Display (automatic in Jupyter)
p.show()

Plot Class

The Plot class is the foundation of the objects interface.

Initialization

so.Plot(data=None, x=None, y=None, color=None, alpha=None,
        fill=None, fillalpha=None, fillcolor=None, marker=None,
        pointsize=None, stroke=None, text=None, **variables)

Parameters:

• data - DataFrame or dict of data vectors
• x, y - Variables for position
• color - Variable for color encoding
• alpha - Variable for transparency
• marker - Variable for marker shape
• pointsize - Variable for point size
• stroke - Variable for line width
• text - Variable for text labels
• **variables - Additional mappings using property names

Examples:

# Basic mapping
so.Plot(df, x='total_bill', y='tip')

# Multiple mappings
so.Plot(df, x='total_bill', y='tip', color='day', pointsize='size')

# All variables in Plot
p = so.Plot(df, x='x', y='y', color='cat')
p.add(so.Dot())  # Uses all mappings

# Some variables in add()
p = so.Plot(df, x='x', y='y')
p.add(so.Dot(), color='cat')  # Only this layer uses color

Methods

add()

Add a layer to the plot with mark and optional stat/move.

Plot.add(mark, *transforms, orient=None, legend=True, data=None,
         **variables)

Parameters:

• mark - Mark object defining visual representation
• *transforms - Stat and/or Move objects for data transformation
• orient - "x", "y", or "v"/"h" for orientation
• legend - Include in legend (True/False)
• data - Override data for this layer
• **variables - Override or add variable mappings

Examples:

# Simple mark
p.add(so.Dot())

# Mark with stat
p.add(so.Line(), so.PolyFit(order=2))

# Mark with multiple transforms
p.add(so.Bar(), so.Agg(), so.Dodge())

# Layer-specific mappings
p.add(so.Dot(), color='category')
p.add(so.Line(), so.Agg(), color='category')

# Layer-specific data
p.add(so.Dot())
p.add(so.Line(), data=summary_df)

facet()

Create subplots from categorical variables.

Plot.facet(col=None, row=None, order=None, wrap=None)

Parameters:

• col - Variable for column facets
• row - Variable for row facets
• order - Dict with facet orders (keys: variable names)
• wrap - Wrap columns after this many

Example:

p.facet(col='time', row='sex')
p.facet(col='category', wrap=3)
p.facet(col='day', order={'day': ['Thur', 'Fri', 'Sat', 'Sun']})

pair()

Create pairwise subplots for multiple variables.

Plot.pair(x=None, y=None, wrap=None, cross=True)

Parameters:

• x - Variables for x-axis pairings
• y - Variables for y-axis pairings (if None, uses x)
• wrap - Wrap after this many columns
• cross - Include all x/y combinations (vs. only diagonal)

Example:

# Pairs of all variables
p = so.Plot(df).pair(x=['a', 'b', 'c'])
p.add(so.Dot())

# Rectangular grid
p = so.Plot(df).pair(x=['a', 'b'], y=['c', 'd'])
p.add(so.Dot(), alpha=0.5)

scale()

Customize how data maps to visual properties.

Plot.scale(**scales)

Parameters: Keyword arguments with property names and Scale objects

Example:

p.scale(
    x=so.Continuous().tick(every=5),
    y=so.Continuous().label(like='{x:.1f}'),
    color=so.Nominal(['#1f77b4', '#ff7f0e', '#2ca02c']),
    pointsize=(5, 10)  # Shorthand for range
)

limit()

Set axis limits.

Plot.limit(x=None, y=None)

Parameters:

• x - Tuple of (min, max) for x-axis
• y - Tuple of (min, max) for y-axis

Example:

p.limit(x=(0, 100), y=(0, 50))

label()

Set axis labels and titles.

Plot.label(x=None, y=None, color=None, title=None, **labels)

Parameters: Keyword arguments with property names and label strings

Example:

p.label(
    x='Total Bill ($)',
    y='Tip Amount ($)',
    color='Day of Week',
    title='Restaurant Tips Analysis'
)

theme()

Apply matplotlib style settings.

Plot.theme(config, **kwargs)

Parameters:

• config - Dict of rcParams or seaborn theme dict
• **kwargs - Individual rcParams

Example:

# Seaborn theme
p.theme({**sns.axes_style('whitegrid'), **sns.plotting_context('talk')})

# Custom rcParams
p.theme({'axes.facecolor': 'white', 'axes.grid': True})

# Individual parameters
p.theme(axes_facecolor='white', font_scale=1.2)

layout()

Configure subplot layout.

Plot.layout(size=None, extent=None, engine=None)

Parameters:

• size - (width, height) in inches
• extent - (left, bottom, right, top) for subplots
• engine - "tight", "constrained", or None

Example:

p.layout(size=(10, 6), engine='constrained')

share()

Control axis sharing across facets.

Plot.share(x=None, y=None)

Parameters:

• x - Share x-axis: True, False, or "col"/"row"
• y - Share y-axis: True, False, or "col"/"row"

Example:

p.share(x=True, y=False)  # Share x across all, independent y
p.share(x='col')  # Share x within columns only

on()

Plot on existing matplotlib figure or axes.

Plot.on(target)

Parameters:

• target - matplotlib Figure or Axes object

Example:

import matplotlib.pyplot as plt

fig, axes = plt.subplots(2, 2, figsize=(10, 10))
so.Plot(df, x='x', y='y').add(so.Dot()).on(axes[0, 0])
so.Plot(df, x='x', y='z').add(so.Line()).on(axes[0, 1])

show()

Render and display the plot.

Plot.show(**kwargs)

Parameters: Passed to matplotlib.pyplot.show()

save()

Save the plot to file.

Plot.save(filename, **kwargs)

Parameters:

• filename - Output filename
• **kwargs - Passed to matplotlib.figure.Figure.savefig()

Example:

p.save('plot.png', dpi=300, bbox_inches='tight')
p.save('plot.pdf')

Mark Objects

Marks define how data is visually represented.

Dot

Points/markers for individual observations.

so.Dot(artist_kws=None, **kwargs)

Properties:

• color - Fill color
• alpha - Transparency
• fillcolor - Alternate color property
• fillalpha - Alternate alpha property
• edgecolor - Edge color
• edgealpha - Edge transparency
• edgewidth - Edge line width
• marker - Marker style
• pointsize - Marker size
• stroke - Edge width

Example:

so.Plot(df, x='x', y='y').add(so.Dot(color='blue', pointsize=10))
so.Plot(df, x='x', y='y', color='cat').add(so.Dot(alpha=0.5))

Line

Lines connecting observations.

so.Line(artist_kws=None, **kwargs)

Properties:

• color - Line color
• alpha - Transparency
• linewidth - Line width
• linestyle - Line style ("-", "--", "-.", ":")
• marker - Marker at data points
• pointsize - Marker size
• edgecolor - Marker edge color
• edgewidth - Marker edge width

Example:

so.Plot(df, x='x', y='y').add(so.Line())
so.Plot(df, x='x', y='y', color='cat').add(so.Line(linewidth=2))

Path

Like Line but connects points in data order (not sorted by x).

so.Path(artist_kws=None, **kwargs)

Properties same as Line.

Example:

# For trajectories, loops, etc.
so.Plot(trajectory_df, x='x', y='y').add(so.Path())

Bar

Rectangular bars.

so.Bar(artist_kws=None, **kwargs)

Properties:

• color - Fill color
• alpha - Transparency
• edgecolor - Edge color
• edgealpha - Edge transparency
• edgewidth - Edge line width
• width - Bar width (data units)

Example:

so.Plot(df, x='category', y='value').add(so.Bar())
so.Plot(df, x='x', y='y').add(so.Bar(color='#1f77b4', width=0.5))

Bars

Multiple bars (for aggregated data with error bars).

so.Bars(artist_kws=None, **kwargs)

Properties same as Bar. Used with Agg() or Est() stats.

Example:

so.Plot(df, x='category', y='value').add(so.Bars(), so.Agg())

Area

Filled area between line and baseline.

so.Area(artist_kws=None, **kwargs)

Properties:

• color - Fill color
• alpha - Transparency
• edgecolor - Edge color
• edgealpha - Edge transparency
• edgewidth - Edge line width
• baseline - Baseline value (default: 0)

Example:

so.Plot(df, x='x', y='y').add(so.Area(alpha=0.3))
so.Plot(df, x='x', y='y', color='cat').add(so.Area())

Band

Filled band between two lines (for ranges/intervals).

so.Band(artist_kws=None, **kwargs)

Properties same as Area. Requires ymin and ymax mappings or used with Est() stat.

Example:

so.Plot(df, x='x', ymin='lower', ymax='upper').add(so.Band())
so.Plot(df, x='x', y='y').add(so.Band(), so.Est())

Range

Line with markers at endpoints (for ranges).

so.Range(artist_kws=None, **kwargs)

Properties:

• color - Line and marker color
• alpha - Transparency
• linewidth - Line width
• marker - Marker style at endpoints
• pointsize - Marker size
• edgewidth - Marker edge width

Example:

so.Plot(df, x='x', y='y').add(so.Range(), so.Est())

Dash

Short horizontal/vertical lines (for distribution marks).

so.Dash(artist_kws=None, **kwargs)

Properties:

• color - Line color
• alpha - Transparency
• linewidth - Line width
• width - Dash length (data units)

Example:

so.Plot(df, x='category', y='value').add(so.Dash())

Text

Text labels at data points.

so.Text(artist_kws=None, **kwargs)

Properties:

• color - Text color
• alpha - Transparency
• fontsize - Font size
• halign - Horizontal alignment: "left", "center", "right"
• valign - Vertical alignment: "bottom", "center", "top"
• offset - (x, y) offset from point

Requires text mapping.

Example:

so.Plot(df, x='x', y='y', text='label').add(so.Text())
so.Plot(df, x='x', y='y', text='value').add(so.Text(fontsize=10, offset=(0, 5)))

Stat Objects

Stats transform data before rendering. Compose with marks in .add().

Agg

Aggregate observations by group.

so.Agg(func='mean')

Parameters:

• func - Aggregation function: "mean", "median", "sum", "min", "max", "count", or callable

Example:

so.Plot(df, x='category', y='value').add(so.Bar(), so.Agg('mean'))
so.Plot(df, x='x', y='y', color='group').add(so.Line(), so.Agg('median'))

Est

Estimate central tendency with error intervals.

so.Est(func='mean', errorbar=('ci', 95), n_boot=1000, seed=None)

Parameters:

• func - Estimator: "mean", "median", "sum", or callable
• errorbar - Error representation:
  • ("ci", level) - Confidence interval via bootstrap
  • ("pi", level) - Percentile interval
  • ("se", scale) - Standard error scaled by factor
  • "sd" - Standard deviation
• n_boot - Bootstrap iterations
• seed - Random seed

Example:

so.Plot(df, x='category', y='value').add(so.Bar(), so.Est())
so.Plot(df, x='x', y='y').add(so.Line(), so.Est(errorbar='sd'))
so.Plot(df, x='x', y='y').add(so.Line(), so.Est(errorbar=('ci', 95)))
so.Plot(df, x='x', y='y').add(so.Band(), so.Est())

Hist

Bin observations and count/aggregate.

so.Hist(stat='count', bins='auto', binwidth=None, binrange=None,
        common_norm=True, common_bins=True, cumulative=False)

Parameters:

• stat - "count", "density", "probability", "percent", "frequency"
• bins - Number of bins, bin method, or edges
• binwidth - Width of bins
• binrange - (min, max) range for binning
• common_norm - Normalize across groups together
• common_bins - Use same bins for all groups
• cumulative - Cumulative histogram

Example:

so.Plot(df, x='value').add(so.Bars(), so.Hist())
so.Plot(df, x='value').add(so.Bars(), so.Hist(bins=20, stat='density'))
so.Plot(df, x='value', color='group').add(so.Area(), so.Hist(cumulative=True))

KDE

Kernel density estimate.

so.KDE(bw_method='scott', bw_adjust=1, gridsize=200,
       cut=3, cumulative=False)

Parameters:

• bw_method - Bandwidth method: "scott", "silverman", or scalar
• bw_adjust - Bandwidth multiplier
• gridsize - Resolution of density curve
• cut - Extension beyond data range (in bandwidth units)
• cumulative - Cumulative density

Example:

so.Plot(df, x='value').add(so.Line(), so.KDE())
so.Plot(df, x='value', color='group').add(so.Area(alpha=0.5), so.KDE())
so.Plot(df, x='x', y='y').add(so.Line(), so.KDE(bw_adjust=0.5))

Count

Count observations per group.

so.Count()

Example:

so.Plot(df, x='category').add(so.Bar(), so.Count())

PolyFit

Polynomial regression fit.

so.PolyFit(order=1)

Parameters:

• order - Polynomial order (1 = linear, 2 = quadratic, etc.)

Example:

so.Plot(df, x='x', y='y').add(so.Dot())
so.Plot(df, x='x', y='y').add(so.Line(), so.PolyFit(order=2))

Perc

Compute percentiles.

so.Perc(k=5, method='linear')

Parameters:

• k - Number of percentile intervals
• method - Interpolation method

Example:

so.Plot(df, x='x', y='y').add(so.Band(), so.Perc())

Move Objects

Moves adjust positions to resolve overlaps or create specific layouts.

Dodge

Shift positions side-by-side.

so.Dodge(empty='keep', gap=0)

Parameters:

• empty - How to handle empty groups: "keep", "drop", "fill"
• gap - Gap between dodged elements (proportion)

Example:

so.Plot(df, x='category', y='value', color='group').add(so.Bar(), so.Dodge())
so.Plot(df, x='cat', y='val', color='hue').add(so.Dot(), so.Dodge(gap=0.1))

Stack

Stack marks vertically.

so.Stack()

Example:

so.Plot(df, x='x', y='y', color='category').add(so.Bar(), so.Stack())
so.Plot(df, x='x', y='y', color='group').add(so.Area(), so.Stack())

Jitter

Add random noise to positions.

so.Jitter(width=None, height=None, seed=None)

Parameters:

• width - Jitter in x direction (data units or proportion)
• height - Jitter in y direction
• seed - Random seed

Example:

so.Plot(df, x='category', y='value').add(so.Dot(), so.Jitter())
so.Plot(df, x='cat', y='val').add(so.Dot(), so.Jitter(width=0.2))

Shift

Shift positions by constant amount.

so.Shift(x=0, y=0)

Parameters:

• x - Shift in x direction (data units)
• y - Shift in y direction

Example:

so.Plot(df, x='x', y='y').add(so.Dot(), so.Shift(x=1))

Norm

Normalize values.

so.Norm(func='max', where=None, by=None, percent=False)

Parameters:

• func - Normalization: "max", "sum", "area", or callable
• where - Apply to which axis: "x", "y", or None
• by - Grouping variables for separate normalization
• percent - Show as percentage

Example:

so.Plot(df, x='x', y='y', color='group').add(so.Area(), so.Norm())

Scale Objects

Scales control how data values map to visual properties.

Continuous

For numeric data.

so.Continuous(values=None, norm=None, trans=None)

Methods:

• .tick(at=None, every=None, between=None, minor=None) - Configure ticks
• .label(like=None, base=None, unit=None) - Format labels

Parameters:

• values - Explicit value range (min, max)
• norm - Normalization function
• trans - Transformation: "log", "sqrt", "symlog", "logit", "pow10", or callable

Example:

p.scale(
    x=so.Continuous().tick(every=10),
    y=so.Continuous(trans='log').tick(at=[1, 10, 100]),
    color=so.Continuous(values=(0, 1)),
    pointsize=(5, 20)  # Shorthand for Continuous range
)

Nominal

For categorical data.

so.Nominal(values=None, order=None)

Parameters:

• values - Explicit values (e.g., colors, markers)
• order - Category order

Example:

p.scale(
    color=so.Nominal(['#1f77b4', '#ff7f0e', '#2ca02c']),
    marker=so.Nominal(['o', 's', '^']),
    x=so.Nominal(order=['Low', 'Medium', 'High'])
)

Temporal

For datetime data.

so.Temporal(values=None, trans=None)

Methods:

• .tick(every=None, between=None) - Configure ticks
• .label(concise=False) - Format labels

Example:

p.scale(x=so.Temporal().tick(every=('month', 1)).label(concise=True))

Complete Examples

Layered Plot with Statistics

(
    so.Plot(df, x='total_bill', y='tip', color='time')
    .add(so.Dot(), alpha=0.5)
    .add(so.Line(), so.PolyFit(order=2))
    .scale(color=so.Nominal(['#1f77b4', '#ff7f0e']))
    .label(x='Total Bill ($)', y='Tip ($)', title='Tips Analysis')
    .theme({**sns.axes_style('whitegrid')})
)

Faceted Distribution

(
    so.Plot(df, x='measurement', color='treatment')
    .facet(col='timepoint', wrap=3)
    .add(so.Area(alpha=0.5), so.KDE())
    .add(so.Dot(), so.Jitter(width=0.1), y=0)
    .scale(x=so.Continuous().tick(every=5))
    .label(x='Measurement (units)', title='Treatment Effects Over Time')
    .share(x=True, y=False)
)

Grouped Bar Chart

(
    so.Plot(df, x='category', y='value', color='group')
    .add(so.Bar(), so.Agg('mean'), so.Dodge())
    .add(so.Range(), so.Est(errorbar='se'), so.Dodge())
    .scale(color=so.Nominal(order=['A', 'B', 'C']))
    .label(y='Mean Value', title='Comparison by Category and Group')
)

Complex Multi-Layer

(
    so.Plot(df, x='date', y='value')
    .add(so.Dot(color='gray', pointsize=3), alpha=0.3)
    .add(so.Line(color='blue', linewidth=2), so.Agg('mean'))
    .add(so.Band(color='blue', alpha=0.2), so.Est(errorbar=('ci', 95)))
    .facet(col='sensor', row='location')
    .scale(
        x=so.Temporal().label(concise=True),
        y=so.Continuous().tick(every=10)
    )
    .label(
        x='Date',
        y='Measurement',
        title='Sensor Measurements by Location'
    )
    .layout(size=(12, 8), engine='constrained')
)

Migration from Function Interface

Scatter Plot

Function interface:

sns.scatterplot(data=df, x='x', y='y', hue='category', size='value')

Objects interface:

so.Plot(df, x='x', y='y', color='category', pointsize='value').add(so.Dot())

Line Plot with CI

Function interface:

sns.lineplot(data=df, x='time', y='measurement', hue='group', errorbar='ci')

Objects interface:

(
    so.Plot(df, x='time', y='measurement', color='group')
    .add(so.Line(), so.Est())
)

Histogram

Function interface:

sns.histplot(data=df, x='value', hue='category', stat='density', kde=True)

Objects interface:

(
    so.Plot(df, x='value', color='category')
    .add(so.Bars(), so.Hist(stat='density'))
    .add(so.Line(), so.KDE())
)

Bar Plot with Error Bars

Function interface:

sns.barplot(data=df, x='category', y='value', hue='group', errorbar='ci')

Objects interface:

(
    so.Plot(df, x='category', y='value', color='group')
    .add(so.Bar(), so.Agg(), so.Dodge())
    .add(so.Range(), so.Est(), so.Dodge())
)

Tips and Best Practices

1. Method chaining: Each method returns a new Plot object, enabling fluent chaining
2. Layer composition: Combine multiple .add() calls to overlay different marks
3. Transform order: In .add(mark, stat, move), stat applies first, then move
4. Variable priority: Layer-specific mappings override Plot-level mappings
5. Scale shortcuts: Use tuples for simple ranges: color=(min, max) vs full Scale object
6. Jupyter rendering: Plots render automatically when returned; use .show() otherwise
7. Saving: Use .save() rather than plt.savefig() for proper handling
8. Matplotlib access: Use .on(ax) to integrate with matplotlib figures