CODEWITHSUNDEEP
javascriptregex
Royi Namir
Royi Namir

Reputation: 148524

Regex - dont mind the order?

I'm trying to crete a regex which can accept general SQL / Js date such as:

31 feb 2012

I already made a regex : 

(0[1-9]|[12]\d|3[01])[ ]+(JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)[ ]+[12]\d{3}$

but how can i tell the regex to ignore the appearence order of the items :

so it can accept : 

  Apr 31 2010
  2010 Apr 31 
  ...
  ...

Upvotes: 0

Views: 78

Answers (2)

Tim Pietzcker
Tim Pietzcker

Reputation: 336108

One solution using lookahead assertions:

var myregexp = /^(?=.*(\b[A-Za-z]{3}\b))(?=.*(\b\d{1,2}\b))(?=.*(\b\d{4}\b))/;
var match = myregexp.exec(subject);
if (match != null) {
    month = match[1];
    days = match[2];
    year = match[3];
}

Explanation:

^             # Start of string
(?=           # Look ahead to see if the following can be matched:
 .*           #  Any number of characters
 (            #  followed by (capturing this in group no. 1)
  \b          #  Start of word
  [A-Za-z]{3} #  Three ASCII letters
  \b          #  End of word
 )            # End of capturing group no. 1
)             # End of lookahead assertion.
(?=           # Look ahead to see if the following can be matched:
 .*           #  Any number of characters
 (            #  followed by (capturing this in group no. 1)
  \b\d{1,2}\b #  a one- or two-digit number
 )            # etc.
)
(?=           # Lookahead no. 3
 .*
 (
  \b\d{4}\b   #  a four-digit number
 )
)

Upvotes: 3

Specksynder
Specksynder

Reputation: 843

You should pool the characters into groups, and then you can use OR to accept them in the different orders in which they occur in your strings. You cannot built a general regex that can work with any order - you have to clearly specify all the orders in which they occur.

Upvotes: 1

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