return a value from a data frame — get_input

Return a single value from a column of a dataframe using the method specified

Usage

get_input_value(data, method = "most_common_value", colname, group = NULL)

Arguments

data: A dataframe which has a column that matches (at least partially) colname
method: How should the value to be returned be selected? Current options include "most_common_value", where the most common input uncertainty value will be returned and "only_value" where all input values must be the same in data; if they are, this value will be returned. Otherwise, an error will be generated.
colname: Column name as a string in data. Note that partial matching and regular expressions can be used.
group: Column name as a string in data used to group the data before calculating the input value to use. Defaults to NULL.

Value

A value of the same type as data[, colname] if group

is NULL, or a data.frame if group is specified.

Details

Note that this function was created intially to return a value to use as the input uncertainty, but it should be generalizable to pulling a value from a column in any data frame using the method specified.

Author

Kathryn Doering

Examples

dfr <- data.frame(
  "year" = 1:5,
  "value" = c(2, 2, 2, 3, 3),
  "se_log" = 0.2
)
SSMSE:::get_input_value(
  data = dfr, method = "most_common_value", colname = "se_log",
  group = "value"
)
#>   value se_log
#> 1     2    0.2
#> 2     3    0.2
SSMSE:::get_input_value(data = dfr, method = "most_common_value", colname = "value")
#> [1] 2
SSMSE:::get_input_value(data = dfr, method = "only_value", colname = "se_log")
#> [1] 0.2
# generates an error:
# SSMSE:::get_input_value(data = dfr, method = "only_value", colname = "value")