Hello I wish to extract the row indices from a data.frame in which a column contains numeric data by calculating the minimum value, but grouped on another column factor:
An example data.frame: Code absdiff NY14/3070 2 NY14/3070 4 NY14/3070 1 NY14/5459 5 NY14/5459 7 So in this case the factor is Code and the numeric vector is absdiff The query would return row indices 3 and 4 which have the minimum values for the factor. I am sure it would involve some combination of which and tapply but cannot figure it out? Many thanks, Barry Dr Barry Rawlins British Geological Survey Keyworth Nottingham NG12 5GG UK Tel: 0115 9363140 Mob: 07884235473 homepage http://sites.google.com/site/barryrawlins/ -- This message (and any attachments) is for the recipient ...{{dropped:8}} ______________________________________________ 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.
