Missing Values In R

Kevin Feasel

2016-07-20

R

David Smith explains NA values in R:

Here’s a little puzzle that might shed some light on some apparently confusing behaviour by missing values (NAs) in R:

What is NA^0 in R?

You can get the answer easily by typing at the R command line:

> NA^0
[1] 1

But the interesting question that arises is: why is it 1? Most people might expect that the answer would be NA, like most expressions that include NA. But here’s the trick to understanding this outcome: think of NA not as a number, but as a placeholder for a number that exists, but whose value we don’t know.

Definitely read the comments on this one.

Related Posts

From Excel to R: Three Examples

Abdul Majed Raja has a few examples of things which are easy to do in Excel and how you can do them in R: Create a difference variable between the current value and the next valueThis is also known as lead and lag – especially in a time series dataset this varaible becomes very important in feature engineering. In […]

Read More

Calculating AUC in R

Andrew Treadway shows how you can calculate Area Under the Curve in R: AUC is an important metric in machine learning for classification. It is often used as a measure of a model’s performance. In effect, AUC is a measure between 0 and 1 of a model’s performance that rank-orders predictions from a model. For […]

Read More

Categories

July 2016
MTWTFSS
« Jun Aug »
 123
45678910
11121314151617
18192021222324
25262728293031