IndexTranslator

class qf_lib.plotting.helpers.index_translator.IndexTranslator(labels_to_locations_dict: Optional[Mapping[str, Number]] = None)[source]

Bases: object

Object which automatically translates label-indexed data into number-indexed data.

Parameters:: labels_to_locations_dict (Mapping[str, Number]) – Contains a mapping from labels to numbers (used as index values for plotting). Must have unique keys and unique values.

Methods:

`inv_translate`(translated_values)	Translates numeric coordinate into label.
`setup_ticks_and_labels`(chart)	Setups ticks' locations and labels in the given chart if it used IndexTranslator.
`translate`(values)	Translates label into numeric coordinate.

inv_translate(translated_values: Union[Number, Sequence[Number]]) → Sequence[str][source]

Translates numeric coordinate into label. Requirement: the Translator must be familiar with mapping the label into numeric coordinate (either the translate must have been called or the labels_to_locations_dict must contain a proper entry).

Parameters:: translated_values – numeric values to be changed into labels (e.g. [0.0, 1.0, 2.0])
Returns:: labels corresponding to numeric values
Return type:: labels

classmethod setup_ticks_and_labels(chart: Chart)[source]: Setups ticks’ locations and labels in the given chart if it used IndexTranslator.

translate(values: Union[str, Sequence[str]]) → Sequence[Number][source]

Translates label into numeric coordinate. If the translation is done for the first time for this value it may modify the state of the translator (it may introduce a new translation).

Parameters:: values – values to be translated (e.g. [“SPY”, “GOOGL”])
Returns:: value translated into numeric coordinate
Return type:: translated values