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Get Unique Values In R Dataframe Column

A dataframe in R is a data structure used to store tabular data in rows and columns. In this tutorial, we will look at how to get the unique values in a column in an R dataframe with the help of some examples.

How do you get unique values from an R dataframe column?

unique values in R dataframe column

You can use the unique() function in R to get the unique values from a dataframe column. Pass the column values as an argument to the function.

The following is the syntax –

unique(dataframe[[columan_name]])

We get a vector of unique values in the given column.

Steps to get distinct values in an R dataframe column

Let’s now look at the steps to follow to get distinct values in a dataframe column 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 – Get the unique values in the column using unique()

To get distinct values in a column, pass the column values vector to the unique() function as an argument. You can use the [[]] notation to get a column’s values vector.

Let’s get the distinct departments from the “Department” column in the above dataframe.

# get distinct values in "Department" column
dept <- unique(employees_df[["Department"]])
# display the vector
print(dept)

Output:

[1] "Sales"      "Accounting" "HR"

We get a vector of the unique values in the “Department” column.

Note that you can also use the column index to access a column’s values. For example, in the above dataframe, the index of the “Department” column is 3 (rows and columns in R are indexed starting from 1).

# get distinct values in "Department" column
dept <- unique(employees_df[[3]])
# display the vector
print(dept)

Output:

[1] "Sales"      "Accounting" "HR"

We get the same result as above.

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Authors

  • Piyush is a data scientist passionate about using data to understand things better and make informed decisions. In the past, he's worked as a Data Scientist for ZS and holds an engineering degree from IIT Roorkee. His hobbies include watching cricket, reading, and working on side projects.