A dataframe in R is a two-dimensional data structure used to store the data in rows and columns. In this tutorial, we will look at how to reorder the columns of a dataframe in R with the help of some examples.
How do you reorder columns of an R dataframe?
The select() function is generally used to select one or more columns from a dataframe in R but you can also use it to reorder the columns.
The following is the syntax –
select(dataframe_input, column_names)
To reorder the columns, pass the dataframe as the first argument and the column names in the order that you want as the subsequent arguments to the select() function.
It returns an R dataframe with the selected columns in the given order.
Steps to reorder columns of a dataframe in R using select() function
Let’s now look at a step-by-step example of reordering columns of a dataframe in R.
Step 1 – Create a dataframe
First, we will create a dataframe that we will be using throughout this tutorial.
# create a dataframe
employees_df = data.frame(
"Name"= c("Jim", "Dwight", "Angela", "Tobi", "Kevin"),
"Age"= c(26, 28, 29, 32, 30),
"Department"= c("Sales", "Sales", "Accounting", "HR", "Accounting")
)
# display the dataframe
print(employees_df)
Output:
Name Age Department 1 Jim 26 Sales 2 Dwight 28 Sales 3 Angela 29 Accounting 4 Tobi 32 HR 5 Kevin 30 Accounting
We now have a dataframe containing information about some employees working in an office. The dataframe has columns “Name”, “Age”, and “Department”.
Step 2 – Import the dplyr package
The select() function is defined in the dplyr package which has to be imported before we can actually use it.
# import dplyr package
library("dplyr")
Here we use the library() function to import the dplyr package.
Step 3 – Select the column using select() function
Let’s say you want the dataframe to have the column order – “Name”, “Department”, and “Age”.
We’ll use the select() function from the dplyr package imported above and pass the column names in the order that we want.
# change column order to - "Name", "Department", "Age" new_df = select(employees_df, "Name", "Department", "Age") # display the dataframe print(new_df)
Output:
Name Department Age 1 Jim Sales 26 2 Dwight Sales 28 3 Angela Accounting 29 4 Tobi HR 32 5 Kevin Accounting 30
We get a dataframe with the desired column order.
Note that you can also use the column indices in the select() function (Rows and columns are indexed starting from 1 in R dataframes).
# change column order to - "Name", "Department", "Age" using thier indices new_df = select(employees_df, 1, 3, 2) # display the dataframe print(new_df)
Output:
Name Department Age 1 Jim Sales 26 2 Dwight Sales 28 3 Angela Accounting 29 4 Tobi HR 32 5 Kevin Accounting 30
We get the same result as above.
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