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How to find the unique values in a column of R dataframe?

  • Last Updated : 21 Apr, 2021

In this article, we will discuss how to find out the unique value in a column of dataframe in R Programming language. For this task, unique() function is used where the column name is passed for which unique values are to be printed.

Syntax: unique(x)

parameters:

  • x: data frame

For a column name select the column using $

dataframe$column_name



Example 1:

R




id<- c(1,2,3,4,5,6,7,8,9)
  
country <- c("INDIA","AMERICA","JAPAN","CHINA","BANGLADESH",
             "SRILANKA","NEPAL","AMERICA","CHINA")
  
data<-data.frame(id,country)
  
unique(data$country)

Output:

[1] INDIA      AMERICA    JAPAN      CHINA      BANGLADESH SRILANKA   NEPAL      

Levels: AMERICA BANGLADESH CHINA INDIA JAPAN NEPAL SRILANKA

Example 2: 

R




data <- data.frame(x1 = c(9, 5, 6, 8, 9),      
                        x2 = c(2, 4, 2, 7, 1), 
                        x3 = c(3,6,7,0,3), 
                        x4 = c("Hello", "value", "value", "geeksforgeeks", NA)
                  
                                                                             
 unique(data[c("x2")])   
 unique(data[c("x1")])

Output:



Unique data in column x2

  x2

1  2

2  4

4  7

5  1

Unique data in column x1

  x1

1  9

2  5

3  6

4  8

Example 3: 

R




data<- data.frame(Student=c('John','Lee','Guy',
                            'John','Lee','Guy'),
                    
                  Age=c(18,19,20,18,19,20),
                    
                  Gender=c('Male','Female','Male',
                           'Male','Female','Male'))
   
unique(data)

Output:




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