Re: [R] Obtaining midpoints of class intervals produced by cut and table
Try this:
library(gsubfn)
demo("gsubfn-cut")
and note the strapply call that converts the levels from cut to a matrix.
On Sun, Nov 8, 2009 at 4:08 PM, jose romero wrote:
> Hello list:
>
> I am using "cut" and "table" to obtain a frequency table from a numeric
> sample vector. The idea is to calculate mean and standard deviation on
> grouped data. However, I can't extract the midpoints of the class intervals,
> which seem to be strings treated as factors. How do i extract the midpoint?
>
> Thanks,
> jose loreto
>
>
> [[alternative HTML version deleted]]
>
>
> __
> R-help@r-project.org mailing list
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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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and provide commented, minimal, self-contained, reproducible code.
Re: [R] Obtaining midpoints of class intervals produced by cut and table
jose romero wrote: Hello list: I am using "cut" and "table" to obtain a frequency table from a numeric sample vector. The idea is to calculate mean and standard deviation on grouped data. However, I can't extract the midpoints of the class intervals, which seem to be strings treated as factors. How do i extract the midpoint? You might consider starting with hist() instead. Otherwise, how about mid <- brk[-1] - diff(brk)/2 where brk is the breakpoints used in cut() -- O__ Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~ - (p.dalga...@biostat.ku.dk) FAX: (+45) 35327907 __ 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.
Re: [R] Obtaining midpoints of class intervals produced by cut and table
Hi,
Maybe something like this (inspired by ?cut),
cut2num <- function(f){
labs <- levels(f)
d <- data.frame(lower = as.numeric( sub("\\((.+),.*", "\\1", labs) ),
upper = as.numeric( sub("[^,]*,([^]]*)\\]", "\\1", labs) ))
d$midpoints <- rowMeans(d)
d
}
a <- c(1, 2, 3, 4, 5, 2, 3, 4, 5, 6, 7)
cut2num(cut(a, 3))
HTH,
baptiste
2009/11/8 jose romero :
> Hello list:
>
> I am using "cut" and "table" to obtain a frequency table from a numeric
> sample vector. The idea is to calculate mean and standard deviation on
> grouped data. However, I can't extract the midpoints of the class intervals,
> which seem to be strings treated as factors. How do i extract the midpoint?
>
> Thanks,
> jose loreto
>
>
> [[alternative HTML version deleted]]
>
>
> __
> 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@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] Obtaining midpoints of class intervals produced by cut and table
Hello list: I am using "cut" and "table" to obtain a frequency table from a numeric sample vector. The idea is to calculate mean and standard deviation on grouped data. However, I can't extract the midpoints of the class intervals, which seem to be strings treated as factors. How do i extract the midpoint? Thanks, jose loreto [[alternative HTML version deleted]] __ 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.
