I think you are describing a situation were each item has a default or "standard" weight--shown in the weight field, but that users frequently need to specify a different weight for the item.
Why do you need to put the weight into the item name field. That greatly complicates your solution and greatly increases the probability that you will encounter problems due to data entry errors. I can think of two possible alternatives that do not require the user to enter the weight in the item name field:
1) Make the weight in the weight field an auto-entered value. It can be looked up from a related table, for example. SInce this is an auto-entered value, users can edit the default value with a different weight when needed.
2) Add another weight field for custom weights. A calculation field can return the custom weight if the field is not empty or the default weight if the custom weight field is empty.
it needs to come from the item name because that is the only customizable field that our cart system can use and we cant have an auto calulation because the weights for these types of orders are so different we basically export a csv from the cart import certain feilds into filemaker then export other fields into a royal mails online postage system we understand that this a very complicated procedure that is why weve been struggling to come up with an answer ourselves. cheers
we cant have an auto calulation because the weights for these types of orders are so different
I would expect them to be different from each item and the auto-enter field options used can enter the value that is appropriate for each item via a table of such values linked in a relationship to your existing table.
If the weight is the last item in the field in every case, this calculation could extract that value from the field:
GetAsNumber ( RightWords ( Yourtable::Item Name ) ; 1 ) )
In some cases, GetAsNumber will not be needed. Using it will remove the units to the right of the number.