[R] reverse lexicographic order

[Thomas W Blackwell]

Murray  -

If you could guarantee that all of the email addresses have
exactly one occurrence of the "@" character in them, then
something like

spit <- do.call("rbind", strsplit(addresses, "@", FALSE))

will produce a data frame with either two or three character
vectors as the columns, in which user name is a separate
column from the domain name.  Now use

spit <- spit[ order(spit[ ,3], spit[ ,1]), ]

to re-sort the data frame by user name within domain name,
and  paste()  to put the columns back together again.

-  tom blackwell  -  u michigan medical school  -  ann arbor  -

On Mon, 15 Dec 2003, Murray Jorgensen wrote:

> Hi all,
>
> I have some email addresses that I would like to sort in reverse
> lexicographic order so that addresses from the same domain will be
> grouped together. How might that be done?
>
> Murray
>
> --
> Dr Murray Jorgensen      http://www.stats.waikato.ac.nz/Staff/maj.html
> Department of Statistics, University of Waikato, Hamilton, New Zealand
> Email: maj at waikato.ac.nz                                Fax 7 838 4155
> Phone  +64 7 838 4773 wk    +64 7 849 6486 home    Mobile 021 1395 862
>
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