On Jun 29, 2010, at 2:54 PM, Stuart Luppescu wrote:
Hello, I have to construct 5 new columns in a data frame depending on
the value of another of the columns in the data frame. The only way I
could figure out to do this was to subset the data frame five times,
do
the variable construction, and then rbind the subsets back together.
Here's part of the code I used:
read001 <- read[read$=="001",]
read001$era1end <- NA
read001$era2base <- NA
read001$era2end <- NA
read001$era3base <- read001$era1base
read001$era3end <- read001$era3base + (6 * read001$era3tr)
read011 <- read[read$existstr=="011",]
read011$era1end <- NA
read011$era2base <- read011$era1base
read011$era2end <- read011$era2base + (4 * read011$era2tr)
read011$era3base <- read011$era2end
read011$era3end <- read011$era2end + (6 * read011$era3tr)
...
?split
processed_list <- split(read, read$existstr)
# then you have the dataframe in sections determined by existstr's value
# process within groups (but your example does not generalize in an
obvious manner.)
# then:
final <- do.call(rbind , processed_list)
--
David.
read2 <- rbind(read001, read011, read100, read110, read111)
Isn't there an easier way to do this?
Thanks.
--
Stuart Luppescu <s...@ccsr.uchicago.edu>
University of Chicago
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David Winsemius, MD
West Hartford, CT
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and provide commented, minimal, self-contained, reproducible code.
