[R] Questions for manipulating datasets in R e.g. sorting and matching

[Stefanie von Felten, IPW&IfU]

Hello everyone,

I want to sort a dataset in R, using multiple columns as sorting 
criteria. I know I can sort a dataset "Data" with 14 columns using one 
column (the fifth), by typing:

DataSort<-Data[order(Data[,5]),1:14]

But how can the dataset be sorted by column 5, then by 6, then by 8?

Another question is, how two datasets can be matched by a column present 
in both of them?

Steffi
-- 
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Stefanie von Felten
Doktorandin

ETH Zürich
Institut für Pflanzenwissenschaften
ETH Zentrum, LFW A 2

Telefon: 044 632 85 97
Telefax: 044 632 11 53
e-mail:  stefanie.vonfelten at ipw.agrl.ethz.ch
http://www.ipw.agrl.ethz.ch/~svfelten/

und:

Universität Zürich
Institut für Umweltwissenschaften
Winterthurerstrasse 190
8057 Zürich

Telefon: 044 635 61 23
Telefax: 044 635 57 11
e-mail:  sfelten at uwinst.unizh.ch
http://www.unizh.ch/uwinst/homepages/steffi.html