Re: obtaining ARRAY position for a given match

From: Scott Bailey <artacus(at)comcast(dot)net>
To:
Cc: Postgresql Mailing List <pgsql-general(at)postgresql(dot)org>
Subject: Re: obtaining ARRAY position for a given match
Date: 2009-11-19 15:56:57
Message-ID: 4B056AC9.2050808@comcast.net
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Pedro Doria Meunier wrote:
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> Hi,
>
> I'm trying to get the array position for a given match as thus:
>
> This gets me the record for a given match:
> SELECT * FROM garmin_units WHERE 'L' = ANY (protocol_tag);
>
> Ok. so far so good...
> But what about getting the array position at which 'L' is stored?
>
> Searching the Postgresql docs gives me no answer... :(
> Am I on a wild goose chase?
>
> Any insight highly appreciated ;)
>
> BR,
> Pedro Doria Meunier.
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I wrote this a while ago. If you are on 8.4 use unnest instead. And if
you are searching thru really big arrays, use plpgsql so you can
terminate when you find a match.

CREATE OR REPLACE FUNCTION idx(text[], text)
RETURNS int AS
$$
SELECT MIN(CASE WHEN $1[i] = $2 THEN i
ELSE NULL END)::int
FROM generate_series(array_lower($1, 1),
array_upper($1, 1)) i;
$$
LANGUAGE 'sql' IMMUTABLE STRICT;

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