The **identical()** function in R can be used to test whether or not two objects in R are exactly equal.

This function uses the following basic syntax:

**identical(x, y, …)**

where:

**x**: The name of an object in R**y**: The name of another object in R

This function returns **TRUE** if the two objects are exactly equal or **FALSE** if they are not.

The following examples show how to use this function to test if two strings, two vectors, and two data frames are exactly equal.

**Example 1: Use identical() to Test if Two Strings are Equal**

The following code shows how to use the **identical()** function to test if two strings are equal:

#define two strings string1 <- 'This is some string' string2 <- 'This is some string' #check if two strings are identical identical(string1, string2) [1] TRUE

The function returns **TRUE** since the two strings are indeed exactly identical.

The following code shows how to use the **identical()** function to test if another two strings are exactly equal:

#define two strings string1 <- 'This is some string' string2 <- 'This is some cool string' #check if two strings are identical identical(string1, string2) [1] FALSE

The function returns **FALSE **since the two strings are not exactly identical.

**Example 2: Use identical() to Test if Two Vectors are Equal**

The following code shows how to use the **identical()** function to test if two vectors are equal:

#define two vectors vector1 <- c('A', 'B', 'C', 'D', 'E', 'F') vector2 <- c('A', 'B', 'C', 'D', 'E', 'F') #check if two vectors are identical identical(vector1, vector2) [1] TRUE

The function returns **TRUE** since the two vectors are indeed exactly identical.

The following code shows how to use the **identical()** function to test if another two vectors are exactly equal:

#define two vectors vector1 <- c('A', 'B', 'C', 'D', 'E', 'F') vector2 <- c('A', 'B', 'C', 'D') #check if two vectors are identical identical(vector1, vector2) [1] FALSE

The function returns **FALSE **since the two vectors are not exactly identical.

**Example 3: Use identical() to Test if Two Data Frames are Equal**

The following code shows how to use the **identical()** function to test if two data frames are equal:

#define two data frames df1 <- data.frame(team=c('A', 'B', 'C', 'D'), points=c(14, 20, 22, 29)) df2 <- data.frame(team=c('A', 'B', 'C', 'D'), points=c(14, 20, 22, 29)) #check if two data frames are equal identical(df1, df2) [1] TRUE

The function returns **TRUE** since the two data frames are indeed exactly identical.

The following code shows how to use the **identical()** function to test if another two data frames are exactly equal:

#define two data frames df1 <- data.frame(team=c('A', 'B', 'C', 'D'), points=c(14, 20, 22, 29)) df2 <- data.frame(team=c('A', 'B', 'C', 'D'), points=c(99, 20, 22, 29)) #check if two data frames are equal identical(df1, df2) [1] FALSE

The function returns **FALSE **since the two data frames are not exactly identical.

**Additional Resources**

The following tutorials explain how to perform other common tasks in R:

How to Use the dim() Function in R

How to Use the transform() Function in R

How to Use the intersect() Function in R