[R] Filtering data
Matt Pocernich
mpocerni at math.cudenver.edu
Wed Nov 7 04:39:54 CET 2001
Hello,
I am having difficulty filtering data. I am working with flow data
collected at a stream gage. For each record, I have a date and flow
value. I have filtered this data to only include days when flow values
exceed a given threshold.
Here is my problem. Within this subset of data, I often have several
consecutive days above the threshold. From this group of days, I wish to
select the record (both date and flow) containing the maximum flow. If an
exceedance is isolated ( the preceeding and succeeding day is below the
threshold) I also wish to select that record.
For example from the data set
Day Flow
1 10
4 13
5 20
6 15
9 13
I would like the 1st, 3rd and 5th record filered.
Any ideas on how I would write such and algorithm would be appreciated.
Thanks,
Matt Pocernich
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