pat_filter() function

[jonathancallahan]

Because we have stuffed the actual tibbles associated with a pat object inside of pat$meta and pat$data we cannot use dplyr filtering on our pat object.

So we need a pat_filter() function which applies the incoming filtering expression to pat$data and returns the modified pat object.

Using pat_filter() should feel just like working with dplyr::filter().

See PWFSLSmoke::monitor_subsetBy() for example code for how to do this.

We already have a pat_filterDate() function that simplifies things for the most common usage and we should provide pat_filterData() that is more general just to be complete.

For extra-completeness, we should have a pat_filter() function that just wraps pat_filterData().

That seems like a good API for end users:

• ~_filter() -- wrapper for ~_filterData() for those expecting dplyr::filter()
• ~_filterDate() -- convenience function; just specify user friendly startdate and enddate
• ~_filterData() -- explicit; does just what it says

[hmrtn]

This can be done using dplyr - so it acts just like dplyr! Keep in mind, returning a pat object does not play well with pipeing as dplyr expects a data.frame. i.e. pat %>% pat_filterData(something>else) %>% group_by(etc) will throw an error.