How To Replace a Group With RegEx?

To use regex pattern within replace() function (aka in javascript) you have to double each backslash, like:  ^(\d\d\.)\d\d$

not sure what exactly you mean with validation for imperial vs. metric.

But if each can be in different format, you shuold be able to achieve it with regex validation. validation expression would look like: (pattern1|pattern2)

ie. each pattern would validate  one type of formatting

Tested, success! Thanks <3

e: Actually -- it seems to be picking up the first pattern in my group but not the latter. Here's my full calc:

if(nIdentifyUnits == "Metric", replace(nMinDepositedWeldMetal,"^(\d\d\.)\d\d$|^(\d\.)\d\d$","Valid"), replace(nMinDepositedWeldMetal,"^(\d.)\d\d\d$","Valid"))

When it's "metric", 55.55 is valid but 5.55 isn't -- I thought that the | would act as "or" (it does in a reg ex right in the control validation itself) and use either of the captures. Any thoughts on that?

PS: Marian update your avatar already

yes, "|" means "or" 

regex pattern(s) are correct. haven't you (accidentally) typed/copied a space around figures?

btw, you could prettify/simplify your regex patterns like

if(nIdentifyUnits == "Metric", replace(nMinDepositedWeldMetal,"^\d{1,2}\.\d{2}$","Valid"), replace(nMinDepositedWeldMetal,"^\d.\d{3}$","Valid"))‍

and if haven't insisted on what format is for what unit system overall formula could be reduced to

replace(nMinDepositedWeldMetal,"^\d{1,2}\.\d{2}$|^\d\.\d{3}$","Valid")‍