In theory I can create a REGEX_REPLACE that turns and integer into a string with thousands separator. I wish AirTable had a FORMAT function but it doesn't, hence the painful work around.
In theory this should work
REGEX_REPLACE({the number}&"","[?<=\\d][?=[?:\\d(3)]+[?!\\d] ",",")
this is based on a match string "(?<=\d)(?=(?:\d{3})+(?!\d))". ( not original I claim no credit, regex match strings give me a nose bleed)
I have learnt the hard way that Airtable uses "[" instead of "(" and you need to escape the
"\\"s - so \\d not \d
Also I have to turn the {the number} field into a string use the &"" trick
The formula doesn't give an error but it doesn't give me the result I want. I just get the number back If I have a number 123456789
I want to return string 123,456,789
I suspect the problem is the "{3}" which has brackets like a field. But what do I know.
Any suggestions?
And the reason I need a string with the thousands separator is so I can put it in an automation email.
The currency field type trick does work.