Creating dummy variables for more than 2 levels

Question

How do I create dummy variables for more than two levels for categorical data in r? I tried model.matrix but it didn’t work.

This has been answered several times over at Cross Validated. You could try searching there(and here too). — NelsonGon, May 07 '19 at 15:47
Here is an interesting [CV thread](https://stats.stackexchange.com/questions/379760/can-a-dummy-variable-take-on-more-than-2-values). It might help you. — NelsonGon, May 07 '19 at 15:58

score 0 · Accepted Answer · answered May 07 '19 at 16:02

0

Read your coulmn as class factor.

Suppose your data is stored in df and categories has the categories you want to convert to dummies. Then:

df$categories <- as.factor(df$categories)

You will not see new columns created. The factor class is a shortcut for this kind of task. Try running a regression model like this and you'll see the results.

answered May 07 '19 at 16:02

Arturo Sbr

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Thanks for helping with my question! as.factor works :) – Paulyn May 08 '19 at 03:57
Good to hear! Vote me up! – Arturo Sbr May 08 '19 at 16:58

Creating dummy variables for more than 2 levels

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