>From your email, it seems like aggregate() is working. Could you please provide the sessionInfo()? My guess is that some other loaded library is masking the summarize(). For example, if I load library(Hmisc) #The following object is masked from ‘package:plyr’: # # is.discrete, summarize
ddply(datNew,.(activity),summarize, max_dt=max(max_dt)) # #Error in is.list(by) : 'by' is missing ddply(datNew,.(activity),plyr::summarize,max_dt=max(max_dt)) # activity max_dt #1 A 2013-03-28 #2 B 2013-03-28 #3 C 2013-03-28 A.K. ----- Original Message ----- From: "Mossadegh, Ramine N." <ramine.mossad...@finra.org> To: arun <smartpink...@yahoo.com> Cc: Sent: Thursday, May 23, 2013 10:44 AM Subject: RE: [R] Removing rows w/ smaller value from data frame Thank but I get : Error in is.list(by) : 'by' is missing When I tried ddply(datNew,.(activity),summarize, max_dt=max(max_dt)) -----Original Message----- From: arun [mailto:smartpink...@yahoo.com] Sent: Thursday, May 23, 2013 10:40 AM To: Mossadegh, Ramine N. Cc: R help Subject: Re: [R] Removing rows w/ smaller value from data frame Hi, Try: datNew<- read.table(text=" activity max_dt A 2013-03-05 B 2013-03-28 A 2013-03-28 C 2013-03-28 B 2013-03-01 ",sep="",header=TRUE,stringsAsFactors=FALSE) datNew$max_dt<- as.Date(datNew$max_dt) aggregate(max_dt~activity,data=datNew,max) # activity max_dt #1 A 2013-03-28 #2 B 2013-03-28 #3 C 2013-03-28 #or library(plyr) ddply(datNew,.(activity),summarize, max_dt=max(max_dt)) # activity max_dt #1 A 2013-03-28 #2 B 2013-03-28 #3 C 2013-03-28 #or ddply(datNew,.(activity),summarize, max_dt=tail(sort(max_dt),1)) # activity max_dt #1 A 2013-03-28 #2 B 2013-03-28 #3 C 2013-03-28 A.K. ----- Original Message ----- From: ramoss <ramine.mossad...@finra.org> To: r-help@r-project.org Cc: Sent: Thursday, May 23, 2013 10:23 AM Subject: [R] Removing rows w/ smaller value from data frame Hello, I have a column called max_date in my data frame and I only want to keep the bigger values for the same activity. How can I do that? data frame: activity max_dt A 2013-03-05 B 2013-03-28 A 2013-03-28 C 2013-03-28 B 2013-03-01 Thank you for your help -- View this message in context: http://r.789695.n4.nabble.com/Removing-rows-w-smaller-value-from-data-frame-tp4667816.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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. Confidentiality Notice: This email, including attachments, may include non-public, proprietary, confidential or legally privileged information. If you are not an intended recipient or an authorized agent of an intended recipient, you are hereby notified that any dissemination, distribution or copying of the information contained in or transmitted with this e-mail is unauthorized and strictly prohibited. If you have received this email in error, please notify the sender by replying to this message and permanently delete this e-mail, its attachments, and any copies of it immediately. You should not retain, copy or use this e-mail or any attachment for any purpose, nor disclose all or any part of the contents to any other person. Thank you ______________________________________________ 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.
