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Date:	Sat, 9 Apr 2005 16:30:50 PDT7
From:	Peter Skye <pskye@peterskye.com >
Reply-To:	scoug-programming@scoug.com
To:	scoug-programming@scoug.com
Subject:	SCOUG-Programming: ArraySort (was: Rexx file rename ?)

Content Type: text/plain

Harry Motin wrote:
>
> Peter,
> Please note the following information from the REXXLIB online help:

Hi Harry, thanks for this info.

I guess I could build a sort key and sort on the key. That's probably
the safest thing to do.
_____

Sort of off topic
=================

Building a sort key is what I do right now when I sort externally. I
just put the sort key plus a delimiter string at the beginning of each
line, sort, and then strip off the sort key.

I use a delimiter rather than just stripping off "n" characters because
the sort keys aren't always the same length, for example if a last name
or a city is part of the sort key.

The delimiter string always starts with a space so that the delimiter
characters won't affect the sort sequence -- otherwise, the records may
end up out-of-sequence (a space is lowest in the sort collating sequence
so it keeps the sort key from affecting the sequence).

Example, using "::" and then " ::" for the delimiter:

key1::data
key12::data
sorts to
key12::data OUT OF SEQUENCE ("2" is less than ":")
key1::data

but

key1 ::data
key12 ::data
sorts to
key1 ::data
key12 ::data

The only thing that can go wrong is if two keys are identical except one
has an extra space on the end. In this case, the sort is not an ordered
sort because the shorter key which should be first will sort so it is
last.

Example:
key1 ::data
key1 ::data THIS KEY HAS ONE TRAILING SPACE
sorts to
key1 ::data OUT OF SEQUENCE
key1 ::data

- Peter

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