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
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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.

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.



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