CODEWITHSUNDEEP
c#regexparsing
inspectorGadget
inspectorGadget

Reputation: 127

Regular expression pattern for dates with different symbols and variable digit formats

I am trying to parse out some dates in a text field that could be in the following formats (note the text field has a bunch of other junk surrounding the dates):

//with dashes
10-10-16
1-5-16
10-1-16
1-10-16

//with periods
10.10.16
1.5.16
10.1.16
1.10.16

//with forward slashes
10/10/16
1/5/16
10/1/16
1/10/16

What I need is one pattern for all digit format scenarios. Here is what I tried: 

//x.xx.xx
Regex reg1 = new Regex (@"\(?\d{1}\)?[-/.]? *\d{2}[-/.]? *[-/.]?\d{2}")

//xx.xx.xx
Regex reg2 = new Regex (@"\(?\d{2}\)?[-/.]? *\d{2}[-/.]? *[-/.]?\d{2}")

//x.x.xx
Regex reg3 = new Regex (@"\(?\d{1}\)?[-/.]? *\d{1}[-/.]? *[-/.]?\d{2}")

//xx.x.xx
Regex reg4 = new Regex (@"\(?\d{2}\)?[-/.]? *\d{1}[-/.]? *[-/.]?\d{2}")

I'm new to regular expressions, so I am looking for a single expression that will handle all these scenarios (ie., digit formats with single number and double digit numbers for -/. in between).

Is there one expression that could handle this?

Thanks,

Upvotes: 0

Views: 52

Answers (3)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 627022

I can suggest

Regex rx = new Regex(@"\(?(?<!\d)\d{1,2}\)?[-/.]?\d{1,2}[-/.]?\d{2}(?!\d)");

If your date separators are used consistently, use the backreference with a capturing group:

Regex rx = new Regex(@"\(?(?<!\d)\d{1,2}\)?([-/.])\d{1,2}\1\d{2}(?!\d)");

See the regex demo 1 and demo 2.

Details:

  • \(? - an optional (
  • (?<!\d) - there must be no digit before the current location
  • \d{1,2} - 1 or 2 digits
  • \)? - an optional )
  • [-/.]? - an optional -, /, or .
  • \d{1,2}[-/.]? - ibid.
  • \d{2} - 2 digits
  • (?!\d) - there must be no digit after the current location.

The version with a capturing group/backreference contains ([-/.]) - a capturing group with ID=1 that matches the first separator, and \1 is the backreference that matches the same text captured into Group 1 (making the second separator to be identical to the first one).

Upvotes: 2

Damitha Shyamantha
Damitha Shyamantha

Reputation: 534

try this 

\d{1,2}(-|\.|\/)\d{1,2}(-|\.|\/)\d{1,2}

Upvotes: 0

Nicolas
Nicolas

Reputation: 7101

You can also try this: \d{1,2}([-./])\d{1,2}\1\d{2}

Regex regex = new Regex(@"\d{1,2}([-./])\d{1,2}\1\d{2}");

  • \d{1,2} between one and two digits
  • ([-./]) any of ., - and /
  • \1 repeat this character another time to (prevent matching 1.1/01 or 1-1.01)
  • \d{2} matches two digits

Upvotes: 0

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