Hello, I want to select same data of a data frame that has information of fish catches:
catch, vessel, trip, day, month, year where trip is the fishing operation number done in each day by each vessel, i.e. for each day, any vesel can have several register of catch corresponding to each operation. >From this data frame I want to do: 1. Add the catches of all trip by vessel and day; then 2. Select rows corresponding to vessels that appear more than 120 days at the year; then 3. Select rows corresponding to vessels that appear mode than 15 years Does anyone know how to do that in R? Thank you in advanced Maria -- View this message in context: http://www.nabble.com/Create-a-data-subset-tp17420700p17420700.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.