# unique Function in R (2 Examples)

On this page you’ll learn how to **remove duplicates from vectors and data frames using the unique function** in R.

The article contains this information:

Here’s the step-by-step process.

## Definition & Basic R Syntax of unique Function
##

**Definition:** The unique R function removes duplicates from data objects.

**Basic R Syntax:** Please find the basic R programming syntax of the unique function below.

unique(x) # Basic R syntax of unique function |

unique(x) # Basic R syntax of unique function

I’ll show in the following two examples how to use the unique function in R programming. So keep on reading…

## Example 1: Return Unique Elements of Vector

Example 1 illustrates how to retain only unique elements of a vector using the unique() function in R. First, we have to create an exemplifying vector:

vec <- c(1, 3, 3, 1, 4, 7, 1) # Create example vector vec # Print example vector # 1 3 3 1 4 7 1 |

vec <- c(1, 3, 3, 1, 4, 7, 1) # Create example vector vec # Print example vector # 1 3 3 1 4 7 1

Our example vector contains seven numeric elements.

Now, we can apply the unique command as shown below:

vec_unique <- unique(vec) # Apply unique() to vector vec_unique # Print updated vector # 1 3 4 7 |

vec_unique <- unique(vec) # Apply unique() to vector vec_unique # Print updated vector # 1 3 4 7

As you can see based on the output of the RStudio console, the unique function extracted only four elements of our original input vector. In other words: three of the vector elements were duplicates.

## Example 2: Return Unique Rows of Data Frame

In this Example, I’ll illustrate how to use the unique function to remove duplicate rows of a data matrix. Again, let’s create some example data:

data <- data.frame(x1 = c(1, 1, 2, 3, 4, 2, 2), # Create example data x2 = c("a", "a", "a", "b", "c", "c", "a")) data # Print example data # x1 x2 # 1 1 a # 2 1 a # 3 2 a # 4 3 b # 5 4 c # 6 2 c # 7 2 a |

data <- data.frame(x1 = c(1, 1, 2, 3, 4, 2, 2), # Create example data x2 = c("a", "a", "a", "b", "c", "c", "a")) data # Print example data # x1 x2 # 1 1 a # 2 1 a # 3 2 a # 4 3 b # 5 4 c # 6 2 c # 7 2 a

Our data table consists of seven rows and two columns. The variable x1 is numeric and the variable x2 is a character string.

Now, let’s apply the unique function to these data:

data_unique <- unique(data) # Apply unique() to data frame data_unique # Print updated data frame # x1 x2 # 1 1 a # 3 2 a # 4 3 b # 5 4 c # 6 2 c |

data_unique <- unique(data) # Apply unique() to data frame data_unique # Print updated data frame # x1 x2 # 1 1 a # 3 2 a # 4 3 b # 5 4 c # 6 2 c

The RStudio console returns only five out of the original seven lines of data. The second and seventh rows were removed.

## Video, Further Resources & Summary

Would you like to learn more about the application of the unique function? Then I can recommend to watch the following video of my YouTube channel. In the video, I’m explaining the R codes of this post in RStudio:

*The YouTube video will be added soon.*

In addition, I can recommend to have a look at the other articles of this website.

- Unique Rows of Data Frame Based On Selected Columns
- Find Unique Combinations of All Elements from Two Vectors
- Count Unique Values in R
- Find Values Contained in First Vector but not Another
- Remove Duplicated Rows from Data Frame
- R Functions List (+ Examples)
- The R Programming Language

To summarize: This article showed how to **apply the unique function** in R programming. If you have any additional comments and/or questions, let me know in the comments section below.

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