Re: [R] Deleting Rows based on Factor and Time Period

alldat$yearmonth <- substr(alldat$mydate, 1, 7) From: Anna Dunietz Cc: "r-help@r-project.org" Sent: Wednesday, September 14, 2011 3:21 AM Subject: Re: [R] Deleting Rows based on Factor and Time Period Mikkel - thank you so much! That's a gr

Re: [R] Deleting Rows based on Factor and Time Period

Alright - for the first stock in the month, I pretty much copied Mikkel's code and got what I wanted. Thanks! Anna install.packages("surveillance") library(surveillance) alldat$year <- isoWeekYear(alldat$mydate)$ISOYear alldat$months<-months(alldat$mydate) alldat <- alldat[order(alldat$year, alld

Re: [R] Deleting Rows based on Factor and Time Period

Mikkel - thank you so much! That's a great start! I could change my demands a bit and pick out the first stock each month. The first stock each week is helpful, but I would need a bigger gap between dates - hence, the first stock a month would be much better. It seems to me, however, that isoWeek

Re: [R] Deleting Rows based on Factor and Time Period

The following will get you the first stock in each week. Is that useful? install.packages("surveillance") library(surveillance) alldat$year <- isoWeekYear(alldat$mydate)$ISOYear alldat$week <- isoWeekYear(alldat$mydate)$ISOWeek alldat <- alldat[order(alldat$year, alldat$week), ] alldat[!duplicated