removeEmptyLevelsDT {R2DT} | R Documentation |
Remove empty levels from all the factor columns of a data.table object
removeEmptyLevelsDT(inputDT)
inputDT |
data.table object containing the data of interest. This is an obligatory argument, without default value. |
No value is returned.
library(data.table) inputDT <- as.data.table(data.frame(x = seq(1, 20, 2), y = LETTERS[1:10])) asFactorDT(inputDT, c('y')) levels(inputDT$y) removeEmptyLevelsDT(inputDT) levels(inputDT$y) removeEmptyLevelsDT(inputDT[x < 10]) levels(inputDT$y) # You need to define a new data.table object # in order to make the 'removeEmptyLevelsDT' function work. reducedDT <- inputDT[x < 10] levels(reducedDT$y) removeEmptyLevelsDT(reducedDT) levels(reducedDT$y)