In this article, we will share with you the usage, the syntax, and how to use the `outer`

in R. The outer() function in R is used to help you apply the function to two vectors in R. Let’s learn more about it with the explanation and examples below.

**Outer In R**

**What does the outer function do in R?**

The outer() function helps you apply the function to two vectors in R. Besides the same mode, this function can also apply to two vectors that have different modes. And you can customize the function by yourself to apply it with two vectors. Let’s take a look at the syntax of the outer() function.

**Syntax**

`outer(x, y, FUN = "*")`

**Parameters**

**x:**The first vector.**y:**The second vector.**FUN:**The function you want to apply with two vectors. The default is multiplied.

**Return value**

The result will be the matrix whose size is (len(x), len(y)).

After learning the usage and the syntax of the outer() function, you will learn how to use this function in the next title below.

**How To Use The Outer In R**

You can add, multiply, divide, or apply the specified function to two vectors by the outer() function in R.

**Multiply two vectors with the outer function**

You can multiply two vectors by the default syntax of the outer() function.

The first vector will multiply each element of the second vector in turn, and the result will be a matrix.

Look at the example below.

# The first vector. vec1 <- c(1, 3, 5, 6, 7) # The second vector vec2 <- c(2, 3) result <- outer(vec1, vec2) result

**Output**

```
[,1] [,2]
[1,] 2 3
[2,] 6 9
[3,] 10 15
[4,] 12 18
[5,] 14 21
```

**Add two vectors with the outer function**

You can add two vectors by assigning the value ‘+’ to the ‘FUN’ parameter.

The first vector will add each element of the second vector in turn, and the result will be a matrix.

Look at the example below.

# The first vector. vec1 <- c(1, 3, 5, 6, 7) # The second vector vec2 <- c(2, 3) result <- outer(vec1, vec2, FUN = "+") result

**Output**

```
[,1] [,2]
[1,] 3 4
[2,] 5 6
[3,] 7 8
[4,] 8 9
[5,] 9 10
```

**Apply the custom function to two vectors**

You can apply the custom function to two vectors by the outer() function.

Look at the example below.

# The first vector vec1 <- c(1, 3, 5, 6, 7) # The second vector vec2 <- c(2, 3) # Create the custom function my_func <- function(a, b) { return(a + 3 * b) } # Apply the 'my_func' function to two vectors result <- outer(vec1, vec2, FUN = my_func) result

**Output**

```
[,1] [,2]
[1,] 7 10
[2,] 9 12
[3,] 11 14
[4,] 12 15
[5,] 13 16
```

**Use the outer function with the character**

You can apply the function to the two character vectors by assigning the value ‘paste’ to the ‘FUN’ parameter.

Look at the example below

# The first vector vec1 <- c("a", "x", "Z") # The second vector vec2 <- c("Y", "k") result <- outer(vec1, vec2, FUN = "paste") result

**Output**

```
[,1] [,2]
[1,] "a Y" "a k"
[2,] "x Y" "x k"
[3,] "Z Y" "Z k"
```

**Summary**

We have shown you the definition, the syntax, and how to use the `outer`

in R. You can use the outer() function in order to apply the function to two vectors in R. We hope this tutorial is helpful to you. Thanks!

My name is Thomas Valen. As a software developer, I am well-versed in programming languages. Don’t worry if you’re having trouble with the C, C++, Java, Python, JavaScript, or R programming languages. I’m here to assist you!

**Name of the university:** PTIT

**Major**: IT

**Programming Languages**: C, C++, Java, Python, JavaScript, R