Dear all,

I have several character strings with a high number of different levels.
unique(x) gives me values in the range of 100-200.
This creates problems as I would like to use them as predictors in a coxph
model.

I therefore would like to convert each of these strings to a new string
(x_new).
x_new should be equal to x for the top n categories (i.e. the top n levels
with the highest occurrence) and NAN elsewhere.
For example, for n=3 x_new would have three levels: The three most common
levels of x + NAN.

Is there some convenient way of doing this?

Thanks in advance,

Michael


Michael Haenlein
Associate Professor of Marketing
ESCP Europe
Paris, France

	[[alternative HTML version deleted]]

