Adds a trend and/or constant to an array.
Parameters: | X : array-like
trend : str {“c”,”t”,”ct”,”ctt”}
prepend : bool
has_constant : str {‘raise’, ‘add’, ‘skip’}
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Returns: | y : array, recarray or DataFrame
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See also
Notes
Returns columns as [“ctt”,”ct”,”c”] whenever applicable. There is currently no checking for an existing trend.