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

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