Re: [R] Help with indexing
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
> -Original Message-
> From: r-help-boun...@r-project.org
> [mailto:r-help-boun...@r-project.org] On Behalf Of Dana Sevak
> Sent: Saturday, November 21, 2009 4:00 PM
> To: r-help@r-project.org
> Subject: [R] Help with indexing
>
> Dear R Helpers,
>
> I am missing something very elementary here, and I don't seem
> to get it from the help pages of the ave, seq and seq_along
> functions, so I wonder if you could offer a quick help.
>
> To use an example from an earlier post on this list, I have a
> dataframe of this kind:
>
> dat = data.frame(name = rep(c("Mary", "Sam", "John"), c(3,2,4)))
> dat$freq = ave(seq_along(dat$name), dat$name, FUN = seq_along)
>
> dat
> name freq
> 1 Mary1
> 2 Mary2
> 3 Mary3
> 4 Sam1
> 5 Sam2
> 6 John1
> 7 John2
> 8 John3
> 9 John4
>
> What I need is another column assigning a number to each name
> starting from index 100, that is:
>
> name freq nb
> 1 Mary1 100
> 2 Mary2 100
> 3 Mary3 100
> 4 Sam1 101
> 5 Sam2 101
> 6 John1 102
> 7 John2 102
> 8 John3 102
> 9 John4 102
>
> What is the easiest way to do this?
match() will do it:
> match(names, unique(names)) + 99
[1] 100 100 100 101 101 102 102 102 102
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
> Thanks a lot for your kind help.
>
> Dana
>
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
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Re: [R] Help with indexing
try this:
> # create a factor and then convert back to numeric
> x$nb <- as.integer(factor(x$name, levels=unique(x$name))) + 99
> x
name freq nb
1 Mary1 100
2 Mary2 100
3 Mary3 100
4 Sam1 101
5 Sam2 101
6 John1 102
7 John2 102
8 John3 102
9 John4 102
On Sat, Nov 21, 2009 at 7:00 PM, Dana Sevak wrote:
> Dear R Helpers,
>
> I am missing something very elementary here, and I don't seem to get it from
> the help pages of the ave, seq and seq_along functions, so I wonder if you
> could offer a quick help.
>
> To use an example from an earlier post on this list, I have a dataframe of
> this kind:
>
> dat = data.frame(name = rep(c("Mary", "Sam", "John"), c(3,2,4)))
> dat$freq = ave(seq_along(dat$name), dat$name, FUN = seq_along)
>
> dat
> name freq
> 1 Mary 1
> 2 Mary 2
> 3 Mary 3
> 4 Sam 1
> 5 Sam 2
> 6 John 1
> 7 John 2
> 8 John 3
> 9 John 4
>
> What I need is another column assigning a number to each name starting from
> index 100, that is:
>
> name freq nb
> 1 Mary 1 100
> 2 Mary 2 100
> 3 Mary 3 100
> 4 Sam 1 101
> 5 Sam 2 101
> 6 John 1 102
> 7 John 2 102
> 8 John 3 102
> 9 John 4 102
>
> What is the easiest way to do this?
>
> Thanks a lot for your kind help.
>
> Dana
>
> __
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
[R] Help with indexing
Dear R Helpers,
I am missing something very elementary here, and I don't seem to get it from
the help pages of the ave, seq and seq_along functions, so I wonder if you
could offer a quick help.
To use an example from an earlier post on this list, I have a dataframe of this
kind:
dat = data.frame(name = rep(c("Mary", "Sam", "John"), c(3,2,4)))
dat$freq = ave(seq_along(dat$name), dat$name, FUN = seq_along)
dat
name freq
1 Mary1
2 Mary2
3 Mary3
4 Sam1
5 Sam2
6 John1
7 John2
8 John3
9 John4
What I need is another column assigning a number to each name starting from
index 100, that is:
name freq nb
1 Mary1 100
2 Mary2 100
3 Mary3 100
4 Sam1 101
5 Sam2 101
6 John1 102
7 John2 102
8 John3 102
9 John4 102
What is the easiest way to do this?
Thanks a lot for your kind help.
Dana
__
R-help@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.
