Hi R users,
I have a data frame, and I generate a date column like this:
df$date = seq(as.Date('2012-01-01'), as.Date('2014-12-31'))
df
A B C
1 2 1
2 2 3
3 2 4
So the data frame has 4 columns now. But when I want to change the values
of column A for specific dates, such as 2012-01-01 to 2013-12-31, I use the
code below:
df[date >= '2012-01-01'&date <= '2013-12-31']$A
df[date >= '2012-01-01'&date <= '2013-12-31']$A +2
But it does not work, the date I generate seems not effective. What is the
problem? Thanks for your help.
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Hello, Try df[df$date >= '2012-01-01'& df$date <= '2013-12-31']$A = etc Hope this helps, Rui Barradas ? Citando lily li <chocold12 at gmail.com>:> Hi R users, > > I have a data frame, and I generate a date column like this: > df$date = seq(as.Date('2012-01-01'), as.Date('2014-12-31')) > > df > A? B? C > 1? 2? ?1 > 2? 2? ?3 > 3? 2? ?4 > > So the data frame has 4 columns now. But when I want to change the values > of column A for specific dates, such as 2012-01-01 to 2013-12-31, I use the > code below: > df[date >= '2012-01-01'&date <= '2013-12-31']$A > df[date >= '2012-01-01'&date <= '2013-12-31']$A +2 > > But it does not work, the date I generate seems not effective. What is the > problem? Thanks for your help. > > ? ? ? ? [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.htmland provide commented, > minimal, self-contained, reproducible code.? [[alternative HTML version deleted]]
> On Jan 29, 2016, at 10:30 PM, lily li <chocold12 at gmail.com> wrote: > > Hi R users, > > I have a data frame, and I generate a date column like this: > df$date = seq(as.Date('2012-01-01'), as.Date('2014-12-31')) > > df > A B C > 1 2 1 > 2 2 3 > 3 2 4 > > So the data frame has 4 columns now. But when I want to change the values > of column A for specific dates, such as 2012-01-01 to 2013-12-31, I use the > code below: > df[date >= '2012-01-01'&date <= '2013-12-31']$A > df[date >= '2012-01-01'&date <= '2013-12-31']$A +2 > > But it does not work, the date I generate seems not effective. What is the > problem? Thanks for your help. >You are using "[" incorrectly. You should be passing that logical vector to the "row-position" of the i,j-form of the `[<-` function. Try instead: df[date >= '2012-01-01'&date <= '2013-12-31' , ]$A df[ date >= '2012-01-01'&date <= '2013-12-31' , ]$A +2 (As it is, I believe you are selecting columns rather than rows.)> [[alternative HTML version deleted]]And study the documentation of your email client so you can learn how to send palin text emails to rhelp.> > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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.David Winsemius Alameda, CA, USA
Sorry, there's a mistake, there's a missing comma, it should be df[df$date >= '2012-01-01'& df$date <= '2013-12-31', ]$A Rui Barradas ? Citando ruipbarradas at sapo.pt:> Hello, > > Try > > df[df$date >= '2012-01-01'& df$date <= '2013-12-31']$A = etc > > Hope this helps, > > Rui Barradas > ? > > Citando lily li <chocold12 at gmail.com>: >> Hi R users, >> >> I have a data frame, and I generate a date column like this: >> df$date = seq(as.Date('2012-01-01'), as.Date('2014-12-31')) >> >> df >> A? B? C >> 1? 2? ?1 >> 2? 2? ?3 >> 3? 2? ?4 >> >> So the data frame has 4 columns now. But when I want to change the values >> of column A for specific dates, such as 2012-01-01 to 2013-12-31, I use the >> code below: >> df[date >= '2012-01-01'&date <= '2013-12-31']$A >> df[date >= '2012-01-01'&date <= '2013-12-31']$A +2 >> >> But it does not work, the date I generate seems not effective. What is the >> problem? Thanks for your help. >> >> ? ? ? ? [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.htmland provide commented, >> minimal, self-contained, reproducible code. > > ? > > ? ? ? ? [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.htmland provide commented, > minimal, self-contained, reproducible code.? [[alternative HTML version deleted]]