Re: [ cf-dev ] Reg Exp

[Paul Johnston]

Whoops! Forgot that bit about the empty string...

basically it's:

^(<regex>)?$

To test for "empty OR regex", as Tim suggested, because ? means 0 or 1 
instances of something.

Paul

Douglas Humphris wrote:

Thanks Paul,

Actually it wasn't so much the date format that I was having problems
with, it was the empty string bit - how do you get a reg exp to return
true for a valid mm/yy OR an empty string?
I've not refined my reg exp to what Tim suggested:
"^([01][0-9]/[0-9]{2})?$" and am just testing for the length of the
string separately.
Douglas

-----Original Message-----
From: Paul Johnston [mailto:[EMAIL PROTECTED] 
Sent: 29 April 2004 10:58
To: [EMAIL PROTECTED]
Subject: Re: [ cf-dev ] Reg Exp

Douglas,

Douglas Humphris wrote:

 

<cfset reCardDate = "^(([0-1]{1,1})([0-9]{1,1})/([0-9]{2,2})){0,1}$"
   

/>
 

<cfset cardStartDate = "" />

<cfoutput>#REFind(reCardDate,cardStartDate)#</cfoutput>

Basically, I want it to return true for the empty string, or for a 
valid mm/yy date format.

   

I'm sure this has been answered by others, but just to add, this is how 
I would do it:

to get the month in mm format, that is going to be anything from 01 to 
12 (not allowing 13-19):
(0[1-9]|1[0-2])
then there's a slash
/
then there's the year formatted correctly
0[0-9]

That year will give you anything from 00 to 09. This can be amended to 
just allow years up until now, or to allow only a certain subset of 
years, eg to allow any year from 1980 onwards up until this year:
((8|9)[0-9]|0[0-4])
or to allow only this year and subsequent five (of course, this would 
fail if it was 2006):
0[#right(1, year(now())#-#right(1, dateadd("y", year(now()))#]
to allow only the next 10 years, guaranteed to work in 3 years time (or 
whenever), create a list delimited by "|" with the two digit years in it

starting from this year and surround it in ().

So the regex allows you to control the data far more than *just* the
format.
Paul

 



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