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 a datetime 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 the Matplotlib units registry. units.registry[datetime.date] = DateConverter()
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 convert themselves to arrays. It also supports 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 register with the Registry converter dictionary and provide a ConversionInterface
. 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 a datetime 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 the Matplotlib units registry.
units.registry[datetime.date] = DateConverter()
The following pages refer to to this document either explicitly or contain code examples using this.
matplotlib.dates
matplotlib.category
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