[R] Re order variables in a dataframe

[Simon Blomberg]

How about to insert a variable a2 inbetween the first and second columns
of dat:

 dat2 <- cbind(dat[,1], a2=a2, dat[,2:3])

Where a2 is the new variable. This mangles the variable name for column
1, unfortunately. Surely someone else will offer a better solution.

Simon.


On Wed, 2009-05-20 at 20:39 -0700, pgseye wrote:
> Thanks Simon,
> 
> I should have explained myself better (although I didn't know about the
> order function so that's handy information).
> 
> I've found a few times, I've added variables to a dataframe that I would
> like to 'group' with variables earlier in the datset. So I was wondering if
> you could somehow ask R, for example, to take that last variable and insert
> it at a different position in the dataframe.
> 
> Thanks,
> 
> Paul
> 
> Simon Blomberg-4 wrote:
> > 
> > Alphabetically, like this?:
> > 
> >> dat <- data.frame(d=rnorm(3), c=rnorm(3), b=rnorm(3), a=rnorm(3))
> >> dat
> >            d          c          b         a
> > 1 -0.1816733 -0.4106008 -0.2855991 -1.022951
> > 2 -1.8326818 -0.6515208  0.3344884 -2.191836
> > 3  1.0924867  0.1159611 -1.3409719  1.195545
> >> dat2 <- dat[,order(names(dat))]
> >> dat2
> >           a          b          c          d
> > 1 -1.022951 -0.2855991 -0.4106008 -0.1816733
> > 2 -2.191836  0.3344884 -0.6515208 -1.8326818
> > 3  1.195545 -1.3409719  0.1159611  1.0924867
> >> 
> > 
> > Cheers,
> > 
> > Simon.
> > 
> > On Wed, 2009-05-20 at 20:19 -0700, pgseye wrote:
> >> This is no doubt a very basic question for most R users, but is there an
> >> easy
> >> way to reorder the variables (columns) in a dataframe (I can't seem to
> >> find
> >> an answer anywhere). I've generally been creating a new dataframe and
> >> selecting the new order I want from the old but this is time-consuming.
> >> 
> >> Thanks,
> >> 
> >> Paul
> > -- 
> > Simon Blomberg, BSc (Hons), PhD, MAppStat. 
> > Lecturer and Consultant Statistician 
> > School of Biological Sciences
> > The University of Queensland 
> > St. Lucia Queensland 4072 
> > Australia
> > Room 320 Goddard Building (8)
> > T: +61 7 3365 2506
> > http://www.uq.edu.au/~uqsblomb
> > email: S.Blomberg1_at_uq.edu.au
> > 
> > Policies:
> > 1.  I will NOT analyse your data for you.
> > 2.  Your deadline is your problem.
> > 
> > The combination of some data and an aching desire for 
> > an answer does not ensure that a reasonable answer can 
> > be extracted from a given body of data. - John Tukey.
> > 
> > ______________________________________________
> > R-help at r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> > http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> > 
> > 
> 
-- 
Simon Blomberg, BSc (Hons), PhD, MAppStat. 
Lecturer and Consultant Statistician 
School of Biological Sciences
The University of Queensland 
St. Lucia Queensland 4072 
Australia
Room 320 Goddard Building (8)
T: +61 7 3365 2506
http://www.uq.edu.au/~uqsblomb
email: S.Blomberg1_at_uq.edu.au

Policies:
1.  I will NOT analyse your data for you.
2.  Your deadline is your problem.

The combination of some data and an aching desire for 
an answer does not ensure that a reasonable answer can 
be extracted from a given body of data. - John Tukey.