tools.tools.add_constant()
statsmodels.tools.tools.add_constant
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statsmodels.tools.tools.add_constant(data, prepend=True, has_constant='skip')
[source] -
Adds a column of ones to an array
Parameters: data : array-like
data
is the column-ordered design matrixprepend : bool
If true, the constant is in the first column. Else the constant is appended (last column).
has_constant : str {‘raise’, ‘add’, ‘skip’}
Behavior if
data
already has a constant. The default will return data without adding another constant. If ‘raise’, will raise an error if a constant is present. Using ‘add’ will duplicate the constant, if one is present.Returns: data : array, recarray or DataFrame
The original values with a constant (column of ones) as the first or last column. Returned value depends on input type.
Notes
When the input is recarray or a pandas Series or DataFrame, the added column’s name is ‘const’.
© 2009–2012 Statsmodels Developers
© 2006–2008 Scipy Developers
© 2006 Jonathan E. Taylor
Licensed under the 3-clause BSD License.
http://www.statsmodels.org/stable/generated/statsmodels.tools.tools.add_constant.html