Unit.nominal(name, data=None, cardinality=None, number_of_instances=1, **kwargs)

Creates a categorical data variable that is an attribute of a Unit

  • name (str) – the name of the variable. If you have data, this should correspond to the column’s name.

  • data (DataVector, optional) – For internal use only.

  • cardinality (int, optional) – The number of unique values that the categorical variable can take. This should correspond to the number of “categories.” If left unspecified, Tisane will infer this from the data.

  • number_of_instances (int, AbstractVariable, or tisane.AtMost, default=1) – This should be the number of measurements of an attribute per unique instance of the associated Unit. For example, if you asked how someone felt 5 different times, the

  • **kwargs (optional) – You can optionally specify the categories using the keyword argument categories. This should be a list. If left unspecified, Tisane will infer this from the data.


The categorical data variable defined as an attribute of this Unit

Return type


See also


create a numeric data variable


create an ordered categorical data variable


A study asked participants how they felt 5 separate times.

>>> import tisane as ts
>>> participant = ts.Unit(name="participant")
>>> feelings = participant.nominal(name="feeling",
...                                categories=["sad", "happy", "angry", "excited"], # optional, specified here as an example
...                                number_of_instances=5)

The study also collected participants’ eye color.

>>> eye_color = participant.nominal(name="eye_color",
                                    categories=["blue", "brown", "green", "hazel", "gray", "black"])