I am trying to calculate monthly means by year of phosphates and nitrates from
a multi year data set. Can anybody help me out with the most effective way to
do this?
My data looks like this:
Collection_Date Test.Name Value
2000-01-24 17:00:00 Phosphate 0.108
2000-01-24 17:00:00 Nitrate 0.037
2001-11-12 08:45:00 Phosphate 0.45
...
Thanks and sorry for the blatantly "newbie" question.
[[alternative HTML version deleted]]
______________________________________________
[email protected] 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.
