Re: how to do a find and replace

On Thu, Nov 17, 2005 at 02:51:05PM -0800, Dawn Buie wrote:
> I'm just confused about how I should write code to update the selected 
> items to remove the 'v.'
> 
> Would I use substring? An example would be much appreciated.

You need a combination of overlay and location.  The following will
work if you always have _only_ 'v.' in there in the one place you
want it.  If it is too early in the string, this _won't_ work:

andrewtest=# SELECT version();                                               version
           
 
-------------------------------------------------------------------------------------------------------PostgreSQL 7.4.7
oni386-pc-linux-gnu, compiled by GCC
 
i386-linux-gcc (GCC) 3.3.5 (Debian 1:3.3.5-12)
(1 ligne)

andrewtest=# SELECT * from mytable ;         location           
----------------------------- /0/v.myimage.jpg/0/v.myotherimage.jpg /0/v.myvthotherimage.jpg
/0/v.myvthotherv.image.jpg
(4 lignes)

Note that I've fiddled with the initial spacing here, in case that
hasn't been totally consistent either.  This is for illustration.

andrewtest=# select overlay(location placing '' from (position('v.'
in location)) for 2) from mytable;         overlay          
--------------------------- /0/myimage.jpg/0/myotherimage.jpg /0/myvthotherimage.jpg /0/myvthotherv.image.jpg
(4 lignes)

Note here that the _second_ 'v.' in the last entry doesn't get pulled
out.  These functions work on the first hit, so this is as expected. 
But if you have something like '/v.0/v.myimage.jpeg' you'll not lose
the 'v.' you want, I expect.

A 


-- 
Andrew Sullivan  | ajs@crankycanuck.ca
The whole tendency of modern prose is away from concreteness.    --George Orwell