Message-ID: <1302137195779-3432250.post@n4.nabble.com>
Date: 2011-04-07T00:46:35Z
From: Brad Patrick Schneid
Subject: unexpected sort order with merge
In-Reply-To: <u1ooc4jxov5.fsf@lx-chrateresearch01.citadelgroup.com>
That is odd, I noticed some weird sorting with merge() a while back too and
always am careful with it now. Fortunately, sort=FALSE seems to work the
way one would think most of the time.
Although, the following results seem weird too! (adding by="date" makes it
not sort oddly, regardless of sort=TRUE or FALSE)
> merge(d1, d2, by="date", sort=F)
date icpn.x foo icpn.y bar
1 Jan 2000 500 1 500 10
2 Feb 2000 500 2 500 20
3 Mar 2000 500 3 500 30
4 Apr 2000 500 4 500 40
5 May 2000 500 5 500 50
6 Jun 2000 500 6 500 60
> merge(d1, d2, by="date", sort=T)
date icpn.x foo icpn.y bar
1 Jan 2000 500 1 500 10
2 Feb 2000 500 2 500 20
3 Mar 2000 500 3 500 30
4 Apr 2000 500 4 500 40
5 May 2000 500 5 500 50
6 Jun 2000 500 6 500 60
> merge(d1, d2, by="date")
date icpn.x foo icpn.y bar
1 Jan 2000 500 1 500 10
2 Feb 2000 500 2 500 20
3 Mar 2000 500 3 500 30
4 Apr 2000 500 4 500 40
5 May 2000 500 5 500 50
6 Jun 2000 500 6 500 60
> merge(d1, d2)
date icpn foo bar
1 Apr 2000 500 4 40
2 Feb 2000 500 2 20
3 Jan 2000 500 1 10
4 Jun 2000 500 6 60
5 Mar 2000 500 3 30
6 May 2000 500 5 50
--
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