The **as.numeric()** function in R is **“used to convert a character vector into a numeric vector”**.

**Syntax**

`as.numeric(character)`

**Parameters**

**character**: It is a character vector to be converted into a numeric vector.

**Return value**

It returns a numeric vector object.

**Example 1: Converting a character vector to a numeric vector**

Create a character vector using the **“c()”** function and convert it into a numeric vector using the **“as.numeric()”** method.

```
rv <- c("-0.1", " 2.7 ", "3")
as.numeric(rv)
```

**Output**

`[1] -0.1 2.7 3.0`

**Example 2: Use of is.numeric() function**

To check if the return value of the **“as.numeric()”** function is numeric, you can use the **“is.numeric()” **method.

```
rv <- c("-0.1", " 2.7 ", "3")
x <- as.numeric(rv)
is.numeric(x)
```

**Output**

`[1] TRUE`

As you can see, the return value from the **as.numeric()** function is a number because **is.numeric() **function returns **TRUE.**

**Example 3: Converting factors to numeric vectors in R**

To **convert** **factors** to the **numeric** **value** in **R**, you can also use the **“as.numeric()” **function.

The **as.numeric()** function will return the factor levels as output and not the factor itself.

If the input is a vector, you can use the **“factor()” **method to convert it into the factor and the **as.numeric() **method to convert the factor into numeric values.

```
rv <- c("Mandalorian", "Ahshoka", "Obiwan")
# convert vector into factor
rf <- factor(rv)
# convert factor into numeric value
x <- as.numeric(rf)
# print the numeric value
x
# check if this is a numeric value
is.numeric(x)
```

**Output**

```
[1] 2 1 3
[1] TRUE
```

You can see that the output is factor levels, a numeric value; that is why the **“is.numeric()” **function returns **TRUE.**

**Example 4: Converting logical vector to numeric vector in R**

Logical vectors whose values are like **“TRUE”** or **“FALSE”** can be converted to numeric values using the **“as.numeric()”** function.

```
vec_logical <- c(FALSE, FALSE, TRUE, TRUE)
vec_num <- as.numeric(vec_logical)
vec_logical
```

**Output**

`[1] FALSE FALSE TRUE TRUE`

**Example 5: Converting a list to a numeric vector in R**

You can use the **as.numeric()** function to convert a **list** to a **numeric** **vector** in R.

Provide a list to the **as.numeric()** function, which returns the **numeric vector**.

```
num_list <- list(11, 21, 19, 46)
number <- as.numeric(num_list)
number
```

**Output**

`[1] 11 21 19 46`

**Example 6: NAs introduced by coercion**

If the **as.numeric()** function cannot convert any element to a number, it returns **NA** for that element.

```
num_list <- list(11, "KL", 19, "KB")
number <- as.numeric(num_list)
number
```

**Output**

```
Warning messages:
1: NAs introduced by coercion
2: NAs introduced by coercion
[1] 11 NA 19 NA
```

The character strings **“KL”** and **“KB”** cannot be converted to numeric values in the above code. That’s why **NAs** are returned.

If the input value is a vector of characters, **as.numeric()** function tries to convert the characters to numbers.

If the input value is a factor, the **as.numeric()** function will return the factor levels as a numeric vector.

Krunal Lathiya is a Software Engineer with over eight years of experience. He has developed a strong foundation in computer science principles and a passion for problem-solving. In addition, Krunal has excellent knowledge of Data Science and Machine Learning, and he is an expert in R Language.