Regex statements for date ranges <=4/1/2009 and <=10/01/2009

Question

Hi,

I need serious help building two Regex statements for a project. The software we're using ONLY accepts Regex for validation.

I need one that fires for any date <4/1/2009

and a second that fires for any date <10/1/2009

My co-worker gave me the following code to check for <=10/01/2010, but it checks leap years and all that stuff. I need something a little more streamlined than this in the MM/DD/YYYY format. Thanks in advance!

^(?:(?:0?[1-9])|(?:1[0-2]))(\/|-|\.)(?:0?[1-9]|1\d|2[0-8])(\/|-|\.)(?:2[0-9][2-9][0-9])$|^(?:(?:0?[1-9])|(?:1[0-2]))(\/|-|\.)(?:0?[1-9]|1\d|2[0-8])(\/|-|\.)(?:201[1-9])$|^(?:(?:(?:0?[13578]|1[02])(\/|-|\.)31)|(?:(?:0?[1,3-9]|1[0-2])(\/|-|\.)(?:29|30)))(\/|-|\.)(?:201[1-9])$|^(?:(?:(?:11)(\/|-|\.))(?:0?[1-9]|1\d|2[0-9]|30)(\/|-|\.))(2010)$|^(?:(?:(?:10|12)(\/|-|\.))(?:0?[1-9]|1\d|2[0-9]|30|31)(\/|-|\.))(2010)$|^(?:(?:0?[1-9])|(?:1[0-2]))(\/|-|\.)(?:0?[1-9]|1\d|2[0-8])(\/|-|\.)(?:2[0-9][2-9][0-9])$|^(?:(?:(?:0?[13578]|1[02])(\/|-|\.)31)\1|(?:(?:0?[1,3-9]|1[0-2])(\/|-|\.)(?:29|30)))(\/|-|\.)(?:2[0-9][2-9][0-9])$|^(?:(?:0?[1-9])|(?:1[0-2]))(\/|-|\.)(?:0?[1-9]|1\d|2[0-8])(\/|-|\.)(?:2011)$|^(?:0?2(\/|-|\.)29\3(?:(?:(?:2[0-9][1-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))$

Answer 1

^(?:(?:0?2/(?:[12][0-9]|0?[1-9])|0?[13]/(?:3[01]|[12][0-9]|0?[1-9]))/2009|(?:0?2/(?:[12][0-9]|0?[1-9])|(?:0?[469]|11)/(?:30|[12][0-9]|0?[1-9])|(?:0?[13578]|1[02])/(?:3[01]|[12][0-9]|0?[1-9]))/(?:200[0-8]|19[0-9]{2}))$

will match any date between 1/1/1900 and 3/31/2009, ignoring leap years but otherwise matching only valid dates;

^(?:(?:0?2/(?:[12][0-9]|0?[1-9])|0?[469]/(?:30|[12][0-9]|0?[1-9])|0?[13578]/(?:3[01]|[12][0-9]|0?[1-9]))/2009|(?:0?2/(?:[12][0-9]|0?[1-9])|(?:0?[469]|11)/(?:30|[12][0-9]|0?[1-9])|(?:0?[13578]|1[02])/(?:3[01]|[12][0-9]|0?[1-9]))/(?:200[0-8]|19[0-9]{2}))$

does the same for 1/1/1900-9/30/2009.

EDIT: It looks like "firing" means "not matching" in your question. So

^(?:(?:(?:0?[469]|11)/(?:30|[12][0-9]|0?[1-9])|(?:0?[578]|1[02])/(?:3[01]|[12][0-9]|0?[1-9]))/2009|(?:0?2/(?:[12][0-9]|0?[1-9])|(?:0?[469]|11)/(?:30|[12][0-9]|0?[1-9])|(?:0?[13578]|1[02])/(?:3[01]|[12][0-9]|0?[1-9]))/(?:[3-9][0-9]{2}|2[1-9][0-9]|20[1-9])[0-9])$

will match any date from 4/1/2009 onwards, and

^(?:(?:11/(?:30|[12][0-9]|0?[1-9])|1[02]/(?:3[01]|[12][0-9]|0?[1-9]))/2009|(?:0?2/(?:[12][0-9]|0?[1-9])|(?:0?[469]|11)/(?:30|[12][0-9]|0?[1-9])|(?:0?[13578]|1[02])/(?:3[01]|[12][0-9]|0?[1-9]))/(?:[3-9][0-9]{2}|2[1-9][0-9]|20[1-9])[0-9])$

will match any date from 10/1/2009 onwards.

All regexes created using RegexMagic.