I'm afraid there's a logic flaw in the format determination in above posts: if the field in question contains ANY non-numeric character, use "%s" else use "%f" with an adaptable width. So, the (var ~...
Not too far off RavinderSingh13's proposal, but with some added felxibility rg. field width, still e.g. some error checking missing :
awk -F, 'function FMT(PAR) {return "%" (PAR~/[^0-9....