Please see the FAQ: What's a reproducible example (`reprex`) and how do I do one? Using a reprex, complete with representative data will attract quicker and more answers.
Let's use the built in dataset mtcars to illustrate an easier way to do this using the dplyr package to remove the wt, qsec and vs variables.
suppressPackageStartupMessages(library(dplyr))
head(mtcars)
#> mpg cyl disp hp drat wt qsec vs am gear carb
#> Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4
#> Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4
#> Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1
#> Hornet 4 Drive 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1
#> Hornet Sportabout 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2
#> Valiant 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1
mtcars %>% select(-wt,-qsec,-vs) %>% head
#> mpg cyl disp hp drat am gear carb
#> Mazda RX4 21.0 6 160 110 3.90 1 4 4
#> Mazda RX4 Wag 21.0 6 160 110 3.90 1 4 4
#> Datsun 710 22.8 4 108 93 3.85 1 4 1
#> Hornet 4 Drive 21.4 6 258 110 3.08 0 3 1
#> Hornet Sportabout 18.7 8 360 175 3.15 0 3 2
#> Valiant 18.1 6 225 105 2.76 0 3 1
Created on 2020-03-27 by the reprex package (v0.3.0)