Re: string_to_array, array_to_string function without separator

pá 15. 3. 2019 v 16:59 odesílatel Chapman Flack <chap(at)anastigmatix(dot)net>
napsal:

> On 3/15/19 11:46 AM, Pavel Stehule wrote:
> > pá 15. 3. 2019 v 15:03 odesílatel David Fetter <david(at)fetter(dot)org>
> napsal:
> >> Whatever optimizations you have in mind for this, could they also work
> >> for string_to_array() and array_to_string() when they get an empty
> >> string handed to them?
> >
> > my idea is use string_to_array('AHOJ') --> {A,H,O,J}
> >
> > empty input means empty result --> {}
>
> I thought the question was maybe about an empty /delimiter/ string.
>
> It seems that string_to_array already has this behavior if NULL is
> passed as the delimiter:
>
> > select string_to_array('AHOJ', null);
> string_to_array
> -----------------
> {A,H,O,J}
>
> and array_to_string has the proposed behavior if passed an
> empty string as the delimiter (as one would naturally expect)
> ... but not null for a delimiter (that just makes the result null).
>
> So the proposal seems roughly equivalent to making string_to_array's
> second parameter optional default null, and array_to_string's second
> parameter optional default ''.
>
> Does that sound right?
>

yes

Pavel

> Regards,
> -Chap
>