[R] Calculate daily means from 5-minute interval data

[Jeff Newmiller]

The general idea is to create a "grouping" column with repeated values for each day, and then to use aggregate to compute your combined results. The dplyr package's group_by/summarise functions can also do this, and there are also proponents of the data.table package which is high performance but tends to depend on altering data in-place unlike most other R data handling functions.

Also pay attention to missing data... if you have any then you will need to consider whether you want the strictness of na.rm=FALSE or permissiveness of na.rm=TRUE for your aggregation functions.

On August 29, 2021 8:08:58 AM PDT, Rich Shepard <rshepard using appl-ecosys.com> wrote:
>I have a year's hydraulic data (discharge, stage height, velocity, etc.)
>from a USGS monitoring gauge recording values every 5 minutes. The data
>files contain 90K-93K lines and plotting all these data would produce a
>solid block of color.
>
>What I want are the daily means and standard deviation from these data.
>
>As an occasional R user (depending on project needs) I've no idea what
>packages could be applied to these data frames. There likely are multiple
>paths to extracting these daily values so summary statistics can be
>calculated and plotted. I'd appreciate suggestions on where to start to
>learn how I can do this.
>
>TIA,
>
>Rich
>
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-- 
Sent from my phone. Please excuse my brevity.