Re: [HACKERS] substring extraction

Karel Zak wrote:

> On Fri, 26 Nov 1999, jose soares wrote:
>
> > Try this:
> >
> > --returns the $2 field delimited by $3
> > drop function field(text,int,text);
> > create function field(text,int,text) returns text as
> > 'declare
> > string text;
> > pos int2:= 0;
> > pos1 int2:= 0;
> > times int2:= 0;
> > totpos int2:= 0;
> > begin
> > times:= $2 - 1;
> > string:= $1;
> > while totpos < times loop
> > string:= substr(string,pos+1);
> > pos:= strpos(string,$3);
> > totpos:= totpos + 1;
> > end loop;
> > string:= substr(string,pos+1);
> > pos1:= strpos(string,$3);
> > return substr(string,1,pos1 - 1);
> > end;
> > ' language 'plpgsql';
> >
>
> Oh, it is great! But my implementation in C for this is
> a little longer (only) :-)
>
> I send this question to the hacker list because "extract delimited
> substring" is not a abnormal uses's request, and (IMHO) will very
> good if this will in PgSQL. How much uses known write this in
> C or any PL?

What about this one:

create function field(text,int,text) returns text as '
return [lindex [split $1 $3] $2]
' language 'pltcl';

It does all the work as long as the third argument is a
single character. For multibyte delimiters it will be
slightly bigger, but not much. Now you might imagine why
PL/Tcl was the first language I created.

Jan

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