The duplicated() function in R is used to get duplicate values in vector or data frame.

The following method shows how to use duplicated function in R with syntax.

Method: Use duplicated() Function

dataframe[duplicated(dataframe$column name), ]  The following example shows how to use this method with example. First create data frame which having duplicate rows in it: # Define data frame df <- data.frame(Machine_name=c("A","B","C","D","A","A","G","B"), Temperature=c(12,9,14,13,18,28,22,23), Pressure=c(20,25,27,29,30,32,39,40)) # Print data frame print(df)  Output:  Machine_name Temperature Pressure 1 A 12 20 2 B 9 25 3 C 14 27 4 D 13 29 5 A 18 30 6 A 28 32 7 G 22 39 8 B 23 40  The output shows data frame with duplicate rows. The following examples shows how to use duplicated() function in R. ## Get Duplicate Rows Using duplicated() Function in R Let’s see how we can use duplicated() function on data frame: # Define data frame df <- data.frame(Machine_name=c("A","B","C","D","A","A","G","B"), Temperature=c(12,9,14,13,18,28,22,23), Pressure=c(20,25,27,29,30,32,39,40)) # Find duplicate rows df[duplicated(df$Machine_name), ]


Output:

Machine_name Temperature Pressure
5            A          18       30
6            A          28       32
8            B          23       40


As we can see in output there are 3 duplicate rows in data frame.

## Count Duplicate Rows Using sum() Function in R

Here is example to count duplicate rows in data frame:

We can count duplicate rows using sum() function.The syntax for this function is sum(duplicated(dataframe$column)). # Define data frame df <- data.frame(Machine_name=c("A","B","C","D","A","A","G","B"), Temperature=c(12,9,14,13,18,28,22,23), Pressure=c(20,25,27,29,30,32,39,40)) # Count duplicate rows sum(duplicated(df$Machine_name))


Output:

[1] 3


Using duplicate() function you can easily find duplicate rows in dataset also, count them.