Here are two different ways with your data as the data.frame xx # Basic R aggregate(xx$Tip, list(xx$Time), sum)
# Using the rshape package library(reshape2) yy <- melt(xx, id=c("Time"), measure.vars=c("Tip")) dcast(yy , Time ~ variable , sum) --- On Thu, 6/9/11, Trying To learn again <tryingtolearnag...@gmail.com> wrote: > From: Trying To learn again <tryingtolearnag...@gmail.com> > Subject: [R] Item analysis > To: r-help@r-project.org > Received: Thursday, June 9, 2011, 4:41 PM > Hi all, > > For several reasons I have no used CARN R in months....I > have an idea and I > want to retry to learn CRAN R. > > I know I need to formulate more "intelligent" questions but > I will expose > and if someone can help me I would be very gratefull I > promise to try to > learn again.... > > The question I have a data file like this: > > Date, Time, Tip > 13/11/2008,23:16:00,432 > 13/01/2009,23:17:00,633 > 13/11/2009,23:16:00,134 > 13/12/2009,23:17:00,234 > 13/01/2010,23:16:00,111 > > I want to make an statistic (the sum of tip) but to extract > one sum by each > different minute in Time, so you see, in this easy example > I will have a > final table with two items: > > Item Sum > 16 (432+134+111) > 17 (633+234) > > Of course in my file (is bigger) I have minutes from 0 to > 59. > > Would it be too much difficult if I want this analysis but > on table for each > day (indentified in the column Date) of the week. So you > see on > 13/11/2008 was thursday so you go each day and sum if > this day is thrusday > from 0 to 59 minutes... > > MAny thanks for all, each tip you give me I will send > thousands of > thanks¡¡¡¡¡ > > [[alternative HTML version deleted]] > > > -----Inline Attachment Follows----- > > ______________________________________________ > 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.