Differences

This shows you the differences between two versions of the page.

--- transformations:rule [2015/04/10 14:47] – elenap
+++ transformations:rule [2019/05/30 06:30] – dmitry
@@ Line 1: / Line 1: @@
 ===== Rule =====
-This transformation calculates new or replaces a column by using nested IF...THEN...ELSE conditions. While the same result can be achieved using an expression with nested [[syntax:functions:if]] functions, the use of Rule transformation is recommended for clarity and readability.
+This action calculates new or replaces existing column by using one or several ordered IF...THEN...ELSE conditions. The conditions are checked one by one until a satisfying condition is found. When a satisfying condition is found, the result is calculated and all other conditions are ignored. When no satisfying condition is found, the default calculation is applied.
-Rule transformation is somewhat similar to //switch// or //case// statements in popular programming languages.
+The order of conditions is significant as conditions are checked starting from the first (top). Therefore conditions that come first have priority over conditions that come after them.
+While the same result can be achieved using an expression with nested [[syntax:functions:if]] functions, the use of Rule action is recommended for clarity, readability, and the ease of rearranging the order.
 EXAMPLE