DT[, coltodelete := NULL]

​

#drop columns by index

df <- mydata[ -c(1,3:4) ]

#drop columns by name

df = subset(mydata, select = -c(x,z))

# Remove third column - by column number

MyMatrix <- MyMatrix[,-3]

​

# Remove third and fifth columns - by feeding the matrix a boolean vector

MyMatrix <- MyMatrix[,c(TRUE,TRUE,FALSE,TRUE,FALSE,TRUE)]

undesired <- c('mpg', 'cyl', 'hp')

​

mtcars <- mtcars %>%

  select(-one_of(undesired))

​

keeps <- c("y", "a")

DF[keeps]

​

DataNAME$ColumnNAME <- NULL