Select only distinct columns

Select all columns that has only one level for a given grouping scope. Useful when dealing with mixed datasets containing both long data and repeated short data.

Usage

select_distinct(df, .by)

Arguments

df

a dataframe

.by

optional grouping columns

Value

df with less columns

Examples

tm = edc_example_ae()
#> Warning: Option "edc_lookup" has been overwritten.
tm$ae %>% names
#> [1] "subjid"  "aesoc"   "aegr"    "n_ae"    "sae"     "crfname"
tm$ae %>% select_distinct() %>% names
#> [1] "crfname"
tm$ae %>% select_distinct(.by=subjid) %>% names
#> [1] "subjid"  "n_ae"    "crfname"