mpl.units

The classes here provide support for using custom classes with matplotlib, e.g., those that do not expose the array interface but know how to converter themselves to arrays. It also supoprts classes with units and units conversion. Use cases include converters for custom objects, e.g., a list of datetime objects, as well as for objects that are unit aware. We don’t assume any particular units implementation, rather a units implementation must provide a ConversionInterface, and the register with the Registry converter dictionary. For example, here is a complete implementation which supports plotting with native datetime objects:

import matplotlib.units as units
import matplotlib.dates as dates
import matplotlib.ticker as ticker
import datetime

class DateConverter(units.ConversionInterface):

    @staticmethod
    def convert(value, unit, axis):
        'convert value to a scalar or array'
        return dates.date2num(value)

    @staticmethod
    def axisinfo(unit, axis):
        'return major and minor tick locators and formatters'
        if unit!='date': return None
        majloc = dates.AutoDateLocator()
        majfmt = dates.AutoDateFormatter(majloc)
        return AxisInfo(majloc=majloc,
                        majfmt=majfmt,
                        label='date')

    @staticmethod
    def default_units(x, axis):
        'return the default unit for x or None'
        return 'date'

# finally we register our object type with a converter
units.registry[datetime.date] = DateConverter()

Functions

is_numlike(obj) return true if obj looks like a number
iterable(obj) return true if obj is iterable

Classes

AxisInfo([majloc, minloc, majfmt, minfmt, ...]) information to support default axis labeling and tick labeling, and
ConversionInterface The minimal interface for a converter to take custom instances (or
Registry() register types with conversion interface