Apply a function to a re-mapped data frame.

Apply a function to a re-mapped data frame.

replyr_apply_f_mapped(
  d,
  f,
  nmap,
  ...,
  restrictMapIn = FALSE,
  rmap = replyr::replyr_reverseMap(nmap),
  restrictMapOut = FALSE
)

Arguments

d	data.frame to work on
f	function to apply.
nmap	named list mapping with keys specifying new column names, and values as original column names.
...	force later arguments to bind by name
restrictMapIn	logical if TRUE restrict columns when mapping in.
rmap	reverse map (for after f is applied).
restrictMapOut	logical if TRUE restrict columns when mapping out.

See also

let, replyr_reverseMap, replyr_mapRestrictCols

Examples

# an external function with hard-coded column names
DecreaseRankColumnByOne <- function(d) {
  d$RankColumn <- d$RankColumn - 1
  d
}

# our example data, with different column names
d <- data.frame(Sepal_Length=c(5.8,5.7),
                Sepal_Width=c(4.0,4.4),
                Species='setosa',rank=c(1,2))
print(d)
#>   Sepal_Length Sepal_Width Species rank
#> 1          5.8         4.0  setosa    1
#> 2          5.7         4.4  setosa    2


# map our data to expected column names so we can use function
nmap <- c(GroupColumn='Species',
          ValueColumn='Sepal_Length',
          RankColumn='rank')
print(nmap)
#>    GroupColumn    ValueColumn     RankColumn 
#>      "Species" "Sepal_Length"         "rank" 

dF <- replyr_apply_f_mapped(d, DecreaseRankColumnByOne, nmap)
print(dF)
#>   Sepal_Length Sepal_Width Species rank
#> 1          5.8         4.0  setosa    0
#> 2          5.7         4.4  setosa    1