R: How to Find Unique Values and Sort Them

You can use the following methods to find unique values and then sort them in R:

Method 1: Find Unique Values in Vector & Sort Them

#get unique values sorted in ascending order
sort(unique(data))

Method 2: Find Unique Rows in Data Frame & Sort Them

#remove duplicate rows in data frame
df_new = df[!duplicated(df), ]

#display unique rows sorted by values in specific column
df_new = df_new[order(df_new$my_column), ]

The following examples show how to use each method in practice.

Example 1: Find Unique Values in Vector & Sort Them

Suppose we have the following vector in R:

#create vector of values
data <- c(2, 2, 4, 7, 2, 4, 14, 7, 10, 7)

We can use the following syntax to find the unique values in the vector and sort them:

#get unique values sorted in ascending order
sort(unique(data))

[1]  2  4  7 10 14

Notice that the unique values from the vector are returned in ascending order.

We can also use the argument decreasing=TRUE to sort the unique values in descending order:

#get unique values sorted in descending order
sort(unique(data), decreasing=TRUE)

[1] 14 10  7  4  2

Notice that the unique values from the vector are returned in descending order.

Example 2: Find Unique Values in Data Frame & Sort Them

Suppose we have the following data frame in R:

#create data frame
df <- data.frame(team=c('A', 'B', 'A', 'A', 'A', 'B', 'B', 'B', 'A', 'B'),
                 points=c(2, 10, 7, 7, 2, 4, 14, 7, 2, 7))

#view data frame
df

   team points
1     A      2
2     B     10
3     A      7
4     A      7
5     A      2
6     B      4
7     B     14
8     B      7
9     A      2
10    B      7

We can use the following syntax to find the unique rows in the data frame and sort them based on the values in the team column:

#remove duplicate rows in data frame
df_new = df[!duplicated(df), ]

#sort unique rows based on values in team column
df_new = df_new[order(df_new$team, df_new$points), ]

#view new data frame
df_new

  team points
1    A      2
3    A      7
2    B      4
6    B      7
7    B     10
8    B     14

Notice that the unique rows are returned and sorted based on the values in the team column, then by the values in the points column.