Add include= argument to tbl_summary()

[ddsjoberg]

When people need to use add_p() with correlated data, the grouped variable must first be included in tbl_summary() and when add_p() sees the variable in add_p(group=) that line is omitted from the summary table.

This process is not intuitive, and when the correlated data field is patient ID, t the summary table takes a very long time to run. Proposed changes:

1. Add include= argument to tbl_summary(). We can easily exclude a data column from the summary table, but it will still be in data= for use in add_p()
2. add_p() will no longer remove rows from tbl_summary. BUT, as this is a breaking change, we need to add a message to users using the old version

• if include = everythinig() AND group= is not missing, we can print a note with the updated code to get the table they are looking for