Re: proposal: searching in array function - array_position - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: proposal: searching in array function - array_position
Date
Msg-id CAFj8pRAXwxo_=HxSSww-DaADfThWb1NKkr4bnpVv-HHwJw7agw@mail.gmail.com
Whole thread Raw
In response to Re: proposal: searching in array function - array_position  (Jim Nasby <Jim.Nasby@BlueTreble.com>)
List pgsql-hackers


2015-01-16 17:57 GMT+01:00 Jim Nasby <Jim.Nasby@bluetreble.com>:
On 1/16/15 3:39 AM, Pavel Stehule wrote:
I am proposing a simple function, that returns a position of element in array.

Yes please!

FUNCTION array_position(anyarray, anyelement) RETURNS int

That won't work on a multi-dimensional array. Ideally it needs to accept a slice or an element and return the specifier for the slice.

theoretically you can use this function for md arrays too. This function returns offset, and you can calculate a Nd possition

so maybe better name -- array_offset or some similar

Regards

Pavel
 

This wouldn't be so bad if we had an easier way to extract subsets of an array, but even that is really ugly because whatever you extract keeps the original number of dimensions.

Implementation is simple (plpgsql code)

This would actually be written in C though, yes? Otherwise it's not really any better than just doing an extension...
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com

pgsql-hackers by date:

Previous
From: Sawada Masahiko
Date:
Subject: Re: Merging postgresql.conf and postgresql.auto.conf
Next
From: Petr Jelinek
Date:
Subject: Re: TABLESAMPLE patch