Hello Kai
This looks like a fun question.
Here is my solution, I'd be curious to see solutions by other people here.
It can also be tweaked in various ways, and easily put into a function
(actually, if you do it - please put it back online :) )
The only thing that might require some work is the rearranging of the
columns.
Cheers,
Tal
######################
# Loading the functions
######################
# Making sure we can source code from github
source("
http://www.r-statistics.com/wp-content/uploads/2012/01/source_https.r.txt";)
# This is based on code first discussed here:
##
http://www.r-statistics.com/2012/01/printing-nested-tables-in-r-bridging-between-the-reshape-and-tables-packages/
# Reading in the function for using merge that reserves order
source_https("
https://raw.github.com/talgalili/R-code-snippets/master/merge.data.frame.r";)
##################
# Make Data
knames <-c('ab', 'aa', 'ac', 'ad', 'ab', 'ac', 'aa', 'ad','ae', 'af')
kdate <- as.Date( c('20111001', '20111102', '20101001', '20100315',
'20101201', '20110105', '20101001', '20110504', '20110603', '20110201'),
format="%Y%m%d")
kdata <- data.frame (knames, kdate)
kdata$kdate <- as.character(kdata$kdate)
##################
# Calculate counts
tmp <- data.frame(table(kdata$kdate))
colnames(tmp)[1] <- "kdate"
tmp[,1] <- as.character(tmp[,1])
# Based on this:
#
http://www.r-statistics.com/2012/01/merging-two-data-frame-objects-while-preserving-the-rows-order/
merge.data.frame(kdata ,tmp ,keep_order = "x")
### Solution:
kdate knames Freq
9 2011-10-01 ab 1
10 2011-11-02 aa 1
2 2010-10-01 ac 2
1 2010-03-15 ad 1
4 2010-12-01 ab 1
5 2011-01-05 ac 1
3 2010-10-01 aa 2
7 2011-05-04 ad 1
8 2011-06-03 ae 1
6 2011-02-01 af 1
----------------Contact
Details:-------------------------------------------------------
Contact me: tal.gal...@gmail.com | 972-52-7275845
Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) |
www.r-statistics.com (English)
----------------------------------------------------------------------------------------------
On Sat, Feb 11, 2012 at 8:17 PM, Kai Mx <govo...@gmail.com> wrote:
> Hi everybody,
> I have a large dataframe similar to this one:
> knames <-c('ab', 'aa', 'ac', 'ad', 'ab', 'ac', 'aa', 'ad','ae', 'af')
> kdate <- as.Date( c('20111001', '20111102', '20101001', '20100315',
> '20101201', '20110105', '20101001', '20110504', '20110603', '20110201'),
> format="%Y%m%d")
> kdata <- data.frame (knames, kdate)
> I would like to add a new variable to the dataframe counting the
> occurrences of different values in knames in their order of appearance
> (according to the date as in indicated in kdate). The solution should be a
> variable with the values 2,2,1,1,1,2,1,2,1,1. I could do it with a loop,
> but there must be a more elegant way to this.
>
> Thanks!
>
> Best,
>
> Kai
>
> [[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.
>
[[alternative HTML version deleted]]
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and provide commented, minimal, self-contained, reproducible code.
