[SQL] regexp_replace behavior

2012-11-20 Thread Marcin Krawczyk 
Hi list,

I'm trying to use regexp_replace to get rid of all occurrences of
certain sub strings from my string.
What I'm doing is:

SELECT regexp_replace('F0301 305-149-101-0 F0302 {x1} 12W47 0635H
{tt}{POL23423423}', E'\{.+\}', '', 'g')

so get rid of whatever is between { } along with these,

but it results in:
'F0301 305-149-101-0 F0302 '

how do I get it to be:
'F0301 305-149-101-0 F0302 12W47 0635H'

??

as I understood the docs, the g flag "specifies replacement of each
matching substring rather than only the first one"
what am I missing ?

regards
mk

Re: [SQL] regexp_replace behavior

2012-11-20 Thread Alvaro Herrera 
Marcin Krawczyk escribió:
> Hi list,
> 
> I'm trying to use regexp_replace to get rid of all occurrences of
> certain sub strings from my string.
> What I'm doing is:
> 
> SELECT regexp_replace('F0301 305-149-101-0 F0302 {x1} 12W47 0635H
> {tt}{POL23423423}', E'\{.+\}', '', 'g')
> 
> so get rid of whatever is between { } along with these,
> 
> but it results in:
> 'F0301 305-149-101-0 F0302 '
> 
> how do I get it to be:
> 'F0301 305-149-101-0 F0302 12W47 0635H'
> 
> ??
> 
> as I understood the docs, the g flag "specifies replacement of each
> matching substring rather than only the first one"

The first \{.+\} match starts at the first { and ends at the last },
eating the {s and }s in the middle.  So there's only one match and that's
what's removed.

> what am I missing ?

You need a non-greedy quantifier.  Try

 SELECT regexp_replace('F0301 305-149-101-0 F0302 {x1} 12W47 0635H 
{tt}{POL23423423}', E'\{.+?\}', '', 'g')

-- 
Álvaro Herrerahttp://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services


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Re: [SQL] regexp_replace behavior

2012-11-20 Thread Marcin Krawczyk 
Yes that's exactly what I needed. Thanks a lot.

pozdrowienia
mk


2012/11/20 Alvaro Herrera 

> Marcin Krawczyk escribió:
> > Hi list,
> >
> > I'm trying to use regexp_replace to get rid of all occurrences of
> > certain sub strings from my string.
> > What I'm doing is:
> >
> > SELECT regexp_replace('F0301 305-149-101-0 F0302 {x1} 12W47 0635H
> > {tt}{POL23423423}', E'\{.+\}', '', 'g')
> >
> > so get rid of whatever is between { } along with these,
> >
> > but it results in:
> > 'F0301 305-149-101-0 F0302 '
> >
> > how do I get it to be:
> > 'F0301 305-149-101-0 F0302 12W47 0635H'
> >
> > ??
> >
> > as I understood the docs, the g flag "specifies replacement of each
> > matching substring rather than only the first one"
>
> The first \{.+\} match starts at the first { and ends at the last },
> eating the {s and }s in the middle.  So there's only one match and that's
> what's removed.
>
> > what am I missing ?
>
> You need a non-greedy quantifier.  Try
>
>  SELECT regexp_replace('F0301 305-149-101-0 F0302 {x1} 12W47 0635H
> {tt}{POL23423423}', E'\{.+?\}', '', 'g')
>
> --
> Álvaro Herrerahttp://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Training & Services
>