I would like to know how can I replace in the values that are below 1 by 1 in a specific column and for the values equal or above 1, I would like to keep the values. I think it is the rule engine that can help me to answer to my problem but I don't know how to manipulate it. Could you in some words, explain me how can i do that ?
Thanks in advance
You are right, the Rule Engine is a good choice for this task. If you specify the default value as the values from the original column (click in the default label than the column name and check the "is a column reference" checkbox) and add a rule with the value $column$ <1 to be replaced by 1, it should work. In the next step you have to replace the original column with the new one if you want.
The other easy option might be the Math Formula node, which is available from the update site (JEP extension). It is as easy as if($myColumn$<1, 1, $myColumn$). Hope this helps. (Int values are not supported as a result, though 2.8 will make that possible.)