The numeric() method creates or coerces objects of type **“numeric”.** The** is.numeric()** is an inbuilt R function used for a more comprehensive test of an object being interpretable as numbers.

Factors are data structures that categorize the data or represent categorical data and save it on multiple levels. They can be saved as integers with an equal label to every unique integer.

**as.numeric in R**

The as.numeric() is a built-in R method that returns a numeric value. To convert factorial value to numeric value in R, use the **as.numeric() **function. The as.numeric() method takes an R object that needs to be coerced and returns the converted numeric value.

The **numeric() **function is identical to **double() **method. It creates a double-precision vector of the defined length with each item equal to **0**. The numeric() method takes a non-negative integer defining the desired length. Double values will be constrained to an integer. If you provide the parameter of length other than one is an error.

The **is.numeric()** is an inbuilt generic R function that checks if the object can be interpretable as numbers or not.

The default method for is.numeric() returns **TRUE** if its parameter is of mode **“numeric”** (which can be of type **“double”** or “**integer**“) and not a factor. Otherwise, it returns **FALSE**.

**Syntax**

```
numeric(length = 0)
as.numeric(x, …)
is.numeric(x)
```

**Parameters**

**length**: It takes a non-negative integer defining the desired length.

**x**: It is an object to be coerced or tested.

**…: **It is the further arguments passed to or from other methods.

**Example**

Let’s define the vector and convert it into a number using **as.numeric()** method.

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

**Output**

`[1] -0.1 2.7 3.0`

To check if the return value of as.numeric() function is number or not, use **is.numeric() **method.

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

**Output**

`[1] TRUE`

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

**Converting Factors to Numeric Values in R**

To convert factors to numeric value in R, use the **as.numeric() **function. If the input is a vector, then use the **factor() **method to convert it into the factor and then use the **as.numeric() **method to convert the factor into numeric values. When a factor is converted into a numeric vector, the numeric codes corresponding to the factor levels will be returned.

```
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, which is a numeric value; that is why **is.numeric() **function returns **TRUE.**

**Converting a Number Factor into Numeric Value**

To convert a number factor into numeric value, use the **as.character() **and **as.numeric() **function. If the factor is a number, then you first need to convert it to a character vector using **as.character() **method and then use the **as.numeric() **method to convert it into numeric.

If a factor is a character, then you need not convert it to a character. And if you try converting an alphabet character to numeric, it will return **NA**.

```
rv <- c(19, 21, 11, 18, 46)
# creating a factor
rf <- factor(rv)
# converting a factor to numeric value
nv <- as.numeric(as.character(rf))
nv
# check if it is numeric value
is.numeric(nv)
```

**Output**

```
[1] 19 21 11 18 46
[1] TRUE
```

**Conclusion**

To convert any vector or factor into numeric value in R, use the **as.numeric() **method. To check if the value is numeric, use the **is.numeric() **method.