C# regular expression to validate a string

Question

I have atext file that contains a lot of records like this:

05/11/04+11:10PM+117+04+0218735793+0'00+00:01'51+TR+

or

05/11/04+11:10PM+117+04+0218735793+0'00+00:01'51+TR+

(without INCOMING)

I want to validate these lines and invalidate all other lines(empty lines or comment lines and corrupted lines.

Is it OK to regular expressions for this purpose?
If yes, what is the regular expression?

Thanks.

Mos def. We don't know if the various fields and delimiters are fixed or variable width, but, yes... this is a good candidate for regex validation. — spender
– spender, Commented Oct 19, 2012 at 9:47

Richard · Accepted Answer · 2012-10-19 10:03:30Z

3

I wouldn't try to use a regex for all of it. For example, you have what looks like a date and a time in there, and a couple of other fields that could be times of some kind, which are tricky to do with regular expressions.

I'd handle this with

String.Split on +
Check you have the right number of fields
Check each field individually depending on what it represents, e.g.
1. DateTime.TryParseExact
2. DateTime.TryParseExact
3. regular expression for 3 digits
4. ...

edited Oct 19, 2012 at 10:03

Richard

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answered Oct 19, 2012 at 9:52

Rawling

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2 Comments

Richard Over a year ago

DateTime.ParseExact throws when the parse fails, if this is likely to happen (ie. erroneous records are expected) better to use DateTime.TryParseExact.

Rawling Over a year ago

Ah, I missed that method. Cheers.

Andrew Cheong · Accepted Answer · 2012-10-19 09:47:46Z

0

^\d\d\/\d\d\/\d\d\+\d\d:\d\d[AP]M\+[\d+':]+\+TR\+$
                                   ^^^^^^^^

I "cheated" in the marked section because I'm not sure exactly what's staying the same, but from the rest of the expression I think you should get the idea.

answered Oct 19, 2012 at 9:47

Andrew Cheong

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Comments

spender · Accepted Answer · 2012-10-19 09:50:45Z

0

var regexPattern = @"^\d{2}/\d{2}/\d{2}\+\d{2}:\d{2}(?:AM|PM)\+\d{3}\+\d{2}" +
                   @"\+\d{10}\+\d'\d{2}\+\d{2}:\d{2}'\d{2}\+TR\+$"

answered Oct 19, 2012 at 9:50

spender

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