Remove Multiple Columns from data.table in R

In this article, we are going to see how to remove multiple columns from data.table in the R Programming language.

Create data.table for demonstration:

R

# load the data.table package
library("data.table")

# create a data.table with 4 columns
# they are id,name,age and address

data = data.table(id = c(1,2,3) ,
                  name = c("sravan","bobby","satwik"),
                  age = c(23,21,17),
                  address = c("kakumanu","ponnur","hyd"))

# display
data

Output:

Here we are going to remove multiple columns by using the index operator []

Syntax: data[ ,’:='(column1 = NULL, column2 = NULL, column n=NULL)]  

where

• data is the input data.table
• column is the columns to be removed
• := is the operator to be loaded in the data.table

Example 1: R program to remove multiple columns from data.table

R

# load the data.table package
library("data.table")

# create a data.table with 4 columns
# they are id,name,age and address

data = data.table(id = c(1,2,3),
                  name = c("sravan","bobby","satwik"),
                  age = c(23,21,17),
                  address = c("kakumanu","ponnur","hyd"))

# remove age , name and address columns
data[ ,':='(age = NULL, address = NULL, name=NULL)]

# display
data

Output:

Example 2: Remove only one column from data.table

R

# load the data.table package
library("data.table")

# create a data.table with 4 columns
# they are id,name,age and address

data = data.table(id = c(1,2,3),
                  name = c("sravan","bobby","satwik"),
                  age = c(23,21,17),
                  address = c("kakumanu","ponnur","hyd"))

# remove id column
data[ ,':='(id=NULL)]

# display
data

Output:

Example 3: R program to remove all columns

R

# load the data.table package
library("data.table")

# create a data.table with 4 columns
# they are id,name,age and address

data = data.table(id = c(1,2,3),
                  name = c("sravan","bobby","satwik"),
                  age = c(23,21,17),
                  address = c("kakumanu","ponnur","hyd"))

# remove all columns
data[ ,':='(id=NULL,age = NULL, address = NULL, name=NULL)]

# display
data

Output:

Null data.table (0 rows and 0 cols)