Re: Some questions about the array.

From: Andrew Dunstan <andrew(at)dunslane(dot)net>
To: YUriy Zhuravlev <u(dot)zhuravlev(at)postgrespro(dot)ru>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Some questions about the array.
Date: 2015-10-09 15:27:02
Message-ID: 5617DCC6.9080605@dunslane.net
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On 10/09/2015 08:02 AM, YUriy Zhuravlev wrote:
> We were some of the issues associated with the behavior of arrays.
> 1. We would like to implement arrays negative indices (from the end) like in
> Python or Ruby: arr[-2] or arr[1: -1]
> but as an array can be indexed in the negative area so it probably can not be
> done.
> 2. We would like to add the ability be omitted boundaries in the slice.
> Example: arr[2:] or arr[:2]. But there was a problem with the update of an
> empty array:
> arr[1:][1:] = {1,2,3,4,5,6} can be interpreted as
> arr[1:3][1:2] or arr[1:2] [1:3] or [1:1], [1:6]
>
> What is the history of the emergence of such arrays? Maybe something can be
> improved?
>
> P.S. I would like List datatype as in Python. Is there any fundamental
> objections? Or we just did not have the time and enthusiasm before?
> The current implementation I would call vectors or matrices but not arrays.
> IMHO
>
>

The name array is now far too baked in to change it.

jsonb and json arrays have many of the characteristics you seem to want.
They are always 0-based and negative indexes count from the end. They
also don't have to be regular, unlike our native arrays.

cheers

andrew

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