Remove or flags groups or clients that have less than some number of rows or some number of distinct values in a variable. For example, it can be used to remove clients that had less than n visits to some service on different dates from some administrative records. It offers filtering with dplyr::n_distinct() functionality for database input.
Arguments
- data
Data.frames or remote tables (e.g., from
dbplyr::tbl_sql())- clnt_id
Grouping variable (quoted/unquoted).
- n_per_clnt
A single number specifying the minimum number of group size.
- count_by
Another variable dictating the counting unit of
n_per_clnt.The default is NULL meaning the inclusion criteria is the number of row, i.e.,dplyr::n() >= n_per_clnt. If it is not NULL, the criteria becomes equivalent todplyr::n_distinct(count_by) >= n_per_clnt.- mode
Either "flag" - add a new column 'flag_restrict_n' indicating if the client met the condition (all rows from a qualified client would have flag = 1), or "filter" - remove clients that did not meet the condition from the data. Default is "flag".
- verbose
A logical for whether to explain the query and report how many groups were removed. Default is fetching from options. Use
options(healthdb.verbose = FALSE)to suppress once and for all. Reporting is not for remote tables as the query is not executed immediately, thus no result is available for summary without adding an extra run (may be slow) of the query.
Value
A subset of input data satisfied the group size requirement, or raw input data with an new flag column.
Examples
# flag cyl groups with less than 8 cars
restrict_n(mtcars, clnt_id = cyl, n_per_clnt = 8, mode = "flag") %>%
head()
#> ℹ Of the 3 clients in the input, 1 were flagged as 0 by restricting that each client must have at least 8 records
#> mpg cyl disp hp drat wt qsec vs am gear carb flag_restrict_n
#> 1 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4 0
#> 2 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4 0
#> 3 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1 1
#> 4 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1 0
#> 5 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2 1
#> 6 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1 0
#remove cyl groups with less than 2 types of gear boxes
restrict_n(mtcars, clnt_id = cyl, n_per_clnt = 3, count_by = gear, mode = "filter")
#> ℹ Of the 3 clients in the input, 1 were excluded by restricting that each client must have at least 3 records with distinct gear
#> mpg cyl disp hp drat wt qsec vs am gear carb flag_restrict_n
#> 1 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4 1
#> 2 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4 1
#> 3 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1 1
#> 4 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 1 1
#> 5 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 4 1
#> 6 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 4 1
#> 7 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 6 1
#> 8 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1 1
#> 9 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2 1
#> 10 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2 1
#> 11 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1 1
#> 12 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2 1
#> 13 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1 1
#> 14 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1 1
#> 15 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1 1
#> 16 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2 1
#> 17 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2 1
#> 18 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2 1