Re: string_to_array with an empty input string

On Wed, Aug 11, 2010 at 1:32 PM, Peter Geoghegan
<peter(dot)geoghegan86(at)gmail(dot)com> wrote:
>> Yeah, I think David's examples are talking about the behavior of join,
>> but we're trying to decide what split should do.  I think the main
>> argument for making it return NULL is that you can then fairly easily
>> use COALESCE() to get whatever you want.  That's a bit more difficult
>> if you use return any other value.
>
> I think that there's a need for additional built-in array functions,
> including one to succinctly test if an array has no elements.

What do you propose? I think the easiest ways to do it right now are:

array_length(arr, 1) is null

or just using an equality test, like this:

arr = '{}'::int[]

> Iterating through an array with plpgsql, for example, is more clunky
> than it should be.

Really?

FOR var IN SELECT UNNEST(arr) LOOP ... END LOOP

I mean, doing everything is sort of clunky in PL/pgsql, but this
doesn't seem particularly bad as PL/pgsql idioms go.

--
Robert Haas
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