Numeric type in R Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a numeric type in R?

A numeric type in R represents numbers that can have decimal points. It is used to store real numbers like 3.14 or 2.0.

beginner

How do you create a numeric variable in R?

You can create a numeric variable by assigning a number with or without decimals, for example: x <- 5 or y <- 3.14.

beginner

What function checks if a value is numeric in R?

The function is.numeric() returns TRUE if the value is numeric, otherwise FALSE.

intermediate

What happens if you add a numeric and an integer in R?

R automatically converts the integer to numeric and performs the addition, returning a numeric result.

intermediate

How can you convert a character string to numeric in R?

Use the as.numeric() function to convert a character string that represents a number into a numeric type.

Which of these is a numeric value in R?

A factor(3)

B 3.14

C TRUE

D "3.14"

3.14 is a numeric value. "3.14" is a character string, TRUE is logical, and factor(3) is a factor.

What does is.numeric(5L) return in R?

A TRUE

B FALSE

C Error

D NA

5L is an integer, but integers are considered numeric in R, so is.numeric returns TRUE.

How do you convert a character "42" to numeric in R?

A numeric("42")

B as.character(42)

C to.numeric("42")

D as.numeric("42")

The correct function to convert character to numeric is as.numeric().

What is the result of 2 + 3.5 in R?

A 5.5

B 5

C "5.5"

D Error

R converts 2 (integer) to numeric and adds 3.5, resulting in 5.5.

Which function checks if a value is numeric?

A is.integer()

B is.character()

C is.numeric()

D is.logical()

is.numeric() checks if a value is numeric.

Explain what a numeric type is in R and how it differs from integer.

Think about numbers with and without decimal points.

Describe how to convert a character string to a numeric value in R and why this might be useful.

Conversion helps when data is read as text but you need numbers.