An empty result instead of an error — gull system handbook

Tip: IFERROR in a gull system rule, so that a missing value leaves the parameter unchanged and the order does not end in an error.

An empty result instead of an error

A rule that does not find a value will leave the parameter unchanged and the order will finish.

Introduction

A rule with an error value, such as `#VALUE!`, fails on an order and the order ends with the status Failed. A rule that returns empty passes and leaves the parameter unchanged.

Steps

1. Wrap the formula in IFERROR. `IFERROR(VLOOKUP([Width], Sizes, 3, FALSE), "")` returns empty when the value is not in the table.
2. Check the result. In the rule editor, open Evaluation → Steps. Every intermediate step shows its value.

Common problems

• The order runs, but the part does not change. `IFERROR` has hidden an error that needs fixing. Use it only where keeping the original value is acceptable.

What next

• Writing a rule. Error values and their causes.
• Functions, tables and variables in rules. VLOOKUP and the other table functions.