[R] remove loop which compares row i to row i-1
ruipbarradas at sapo.pt
Thu Jul 12 23:11:08 CEST 2012
I've not been following this thread but this seems ndependent from
previous posts. Try the following.
url <- "http://r.789695.n4.nabble.com/file/n4636337/BR3_2011_New.csv"
tUnitsort <- read.csv(url, header=TRUE)
cols <- sapply(c("Date", "Hour", "BlockNumber", "MyTo"), function(x)
# This does it
# Use full data.frame 'tUnitsort' if you want
data.tmp <- aggregate(MyTo ~ Date + Hour, data = tUnitsort[, cols], max)
data.tmp <- merge(tUnitsort[, cols], data.tmp, by=c("Date", "Hour"))
# Make it pretty
idx <- grep("MyTo", names(data.tmp))
names(data.tmp)[idx] <- c("MyTo", "NewColumn")
# See it
Also, you should quote the context. Many, almost all of us do NOT read
the posts on Nabble. And Nabble does have a "quote" button.
Hope this helps,
Em 12-07-2012 18:55, jcrosbie escreveu:
> Thank you,
> I am sorry but I am still trying to figure out how to make the function
> I have a column called tUnitsort$BlockNumber which can range from 0 to 6.
> I have another two columns with the date and the hour ending for the given
> Date Hour BlockNumber MyTo NewColumn
> 2011-01 1 2 140 140
> 2011-01 1 1 70 140
> 2011-01 1 0 0 140
> 2011-02 1 2 160 160
> 2011-02 1 1 70 160
> 2011-02 1 0 0 160
> 2011-03 1 2 150 150
> I want to create a NewColumn which will place the MyTo number for the
> highest block number for the rest blocks in a given hour ending within a
> I am unsure how to refference the element before in this case. I thought
> the -1 was doing this but I believe I'm wrong now.
> View this message in context: http://r.789695.n4.nabble.com/remove-loop-which-compares-row-i-to-row-i-1-tp4635327p4636337.html
> Sent from the R help mailing list archive at Nabble.com.
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> and provide commented, minimal, self-contained, reproducible code.
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