Get a vector with all unique values found in a given column of a data.frame.
Concatenated values (A,B) in the column can be returned as single values
(A and B).
Arguments
- .data
Data frame. Data.frame to select column from.
- column
Character or integer. Quoted or unqoted column name or column position.
- split
Character (vector). Character or regular expression(s) passed to
strsplit()to split column values before returning unique values. Defaults to,.
Examples
# Set default connection variable
con <- connect_to_etn()
#> Error: nanodbc/nanodbc.cpp:1135: 00000: [unixODBC][Driver Manager]Data source name not found and no default driver specified
library(dplyr) # For %>%
#>
#> Attaching package: ‘dplyr’
#> The following objects are masked from ‘package:stats’:
#>
#> filter, lag
#> The following objects are masked from ‘package:base’:
#>
#> intersect, setdiff, setequal, union
# List unique scientific_name from a dataframe containing animal information
df <- get_animals(con, animal_project_code = "2014_demer")
#> Error in methods::is(connection, "PostgreSQL"): object 'con' not found
list_values(df, "scientific_name")
#> Error: .data is not a data frame
# Or using pipe and unquoted column name
df %>% list_values(scientific_name)
#> Error: .data is not a data frame
# Or using column position
df %>% list_values(8)
#> Error: .data is not a data frame
# tag_serial_number can contain comma-separated values
df <- get_animals(con, animal_id = 5841)
#> Error in methods::is(connection, "PostgreSQL"): object 'con' not found
df$tag_serial_number
#> Error in df$tag_serial_number: object of type 'closure' is not subsettable
# list_values() will split those and return unique values
list_values(df, tag_serial_number)
#> Error: .data is not a data frame
# Another expression can be defined to split values (here ".")
list_values(df, tag_serial_number, split = "\\.")
#> Error: .data is not a data frame