Re: Regex Character-Class

Henry schrieb:
> I must be missing something here:
>
> SELECT '1.1.1.1' ~ E'^\d+';
>
> returns FALSE, when I would expect TRUE, as for:
>
> SELECT '1.1.1.1'  ~ E'^[[:digit:]]+';
>
> ie, '[[:digit:]]'  !=  '\d'
>
> In config, "regex_flavor = advanced".
>
> Any ideas?

Yes; you have to escape the backslash character:

=> SELECT '1.1.1.1' ~ E'^\\d+';
  ?column?
----------
  t
(1 row)


See the documentation for this
(http://www.postgresql.org/docs/8.3/interactive/functions-matching.html):

   Note:  Remember that the backslash (\) already has a special meaning
   in PostgreSQL string literals. To write a pattern constant that
   contains a backslash, you must write two backslashes in the statement,
   assuming escape string syntax is used (see Section 4.1.2.1).

Ciao,
Thomas