Drop selected variables

Quickly drop variables by either column names or positions.

Usage

drop_columns(data, ind)

Arguments

data

input data

ind

a vector of either names or column positions of the variables to be dropped.

Details

This function updates data.table object directly. Otherwise, output data will be returned matching input object class.

Examples

# Load packages
library(data.table)

# Generate data
dt <- data.table(sapply(setNames(letters, letters), function(x) {assign(x, rnorm(10))}))
dt2 <- copy(dt)

# Drop variables by name
names(dt)
#>  [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s"
#> [20] "t" "u" "v" "w" "x" "y" "z"
drop_columns(dt, letters[2L:25L])
names(dt)
#> [1] "a" "z"

# Drop variables by column position
names(dt2)
#>  [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s"
#> [20] "t" "u" "v" "w" "x" "y" "z"
drop_columns(dt2, seq(2, 25))
names(dt2)
#> [1] "a" "z"

# Return from non-data.table input
df <- data.frame(sapply(setNames(letters, letters), function(x) {assign(x, rnorm(10))}))
drop_columns(df, letters[2L:25L])
#>              a           z
#> 1  -0.21223603 -0.42349012
#> 2  -0.90634018 -0.19838706
#> 3  -2.10215248 -0.89480241
#> 4   1.89336046  0.90426912
#> 5  -0.96812584  0.07964921
#> 6  -0.10260304 -1.25882722
#> 7   0.23995957  1.02568511
#> 8   0.06089889 -0.73077860
#> 9  -2.17757603 -0.19014551
#> 10 -0.11786014  0.52886469