Simple Regex issue

[CJ]

I'm not an expert on regular expressions, but I thought I knew how to
construct simple ones

I have two very simple regular expresions:
"|1|(?<dt>\d\d-\d\d-\d\d\d\d).*" and ".*(?<dt>\d\d-\d\d-\d\d\d\d).*"
With the input string @"|1|01-08-2005 12:57:12", both regular
expressions match. But the named group dt is correct for the second
expression (01-08-2005) and just an empty string for the first, which
just doesn't make much sense to me.

 

[mdb]

I'm not an expert on regular expressions, but I thought I knew how to
construct simple ones

I have two very simple regular expresions:
"|1|(?<dt>\d\d-\d\d-\d\d\d\d).*" and ".*(?<dt>\d\d-\d\d-\d\d\d\d).*"
With the input string @"|1|01-08-2005 12:57:12", both regular
expressions match. But the named group dt is correct for the second
expression (01-08-2005) and just an empty string for the first, which
just doesn't make much sense to me.

The | is a special character in a Regex... it means "this or that" (whatever
is before or after the | character.) So in this case, you are probably
matching the empty string before the first | in the first Regex. If you want
those characters to match explicitly, escape them:

\|1\|(?<dt>\d\d-\d\d-\d\d\d\d).*

 

[Wessel Troost]

I have two very simple regular expresions:

"|1|(?<dt>\d\d-\d\d-\d\d\d\d).*" and ".*(?<dt>\d\d-\d\d-\d\d\d\d).*"
With the input string @"|1|01-08-2005 12:57:12", both regular
expressions match. But the named group dt is correct for the second
expression (01-08-2005) and just an empty string for the first, which
just doesn't make much sense to me.

Your first expression uses the | operator, which is regex for "or". If
you escape it, it should work fine:

"\|1\|(?<dt>\d\d-\d\d-\d\d\d\d).*"

Greetings,
Wessel

 

[CJ]

Oh, of course. Should have thought of that ...

thanks