busdayaxis 0.0.1

Business day axis scale for matplotlib

busdayaxis

Business-day axis support for Matplotlib.

busdayaxis provides a custom Matplotlib scale that compresses non-business days and displays time in continuous business-day space.

• Useful when your data has no weekend activity and is naturally defined in business-day units.
• Integrates directly with Matplotlib’s transformation and autoscaling machinery.
• No data preprocessing is required.
• Custom business calendars are supported.

Motivation

Many time series evolve in business time rather than calendar time:

• Equity prices
• Trading signals
• Portfolio returns
• Risk metrics
• Operational KPIs

When plotted on a standard calendar axis, weekends introduce artificial gaps that visually distort slopes and compress active trading periods. busdayaxis removes these inactive periods by mapping calendar datetimes to continuous business-day units.

Installation

You can install using pip:

pip install busdayaxis

Quick Start

import matplotlib.pyplot as plt
import busdayaxis

busdayaxis.register_scale()

ax.plot(dates, values)
ax.set_xscale("busday")

Custom Business Calendars

The scale supports all keyword arguments accepted by NumPy’s business-day functions (is_busday, busday_count, busday_offset). This allows custom weekmasks and holiday lists.

ax.set_xscale(
    "busday",
    weekmask="Mon Tue Wed Thu Fri",
    holidays=["2025-01-01", "2025-12-25"],
)

This makes it possible to model exchange holidays or company-specific calendars.

Matplotlib Integration

• The busday scale is implemented as a proper ScaleBase subclass and:
• Participates in Matplotlib’s transform pipeline
• Works with autoscaling
• Works with shared axes and subplots
• Supports all artists that go through the standard data transformation system
• This includes plot, scatter, bar, vlines, fill_between, and other common Matplotlib objects.

License

BSD 3-Clause