convert text to number

maryamshirzad

hi
i have one column that its type is text. but shows in rapidminer as polynominal. i want this column convert to numeric.
for example, value of this column is "A","B","C" now i want convert to 1,2,3.How is this done?

Telcontar120

Nominal to Numerical operator will do that for you if you select "unique integers" in the parameters as the conversion method under "coding type."  See the help description of that operator for more details.

Telcontar120

You can use the Map operator to specify values.
Or you can use Nominal to Numerical to allow it to recode automatically.
In either case, be careful what you do with the resulting numerical data!  It is not often the case that a strict numerical substitution like this is suitable for use in ML algorithms.

maryamshirzad

nominal to numeric operator just converted to 0 and 1.but map operator, in option of this operator I need to specify the previous text and the number to be replaced. But I want the operator to do it automatically. ie 

Recognize values in the column and replace with Appropriate number

Telcontar120

Nominal to Numerical operator will do that for you if you select "unique integers" in the parameters as the conversion method under "coding type."  See the help description of that operator for more details.

maryamshirzad

That's exactly my answer. Thank you very much for your help.