Special Numeric Values :: SAS/IML(R) 13.1 User's Guide

The R language has four symbols that are used to represent special numerical values.

The symbol NA represents a missing value.
The symbol Inf represents positive infinity.
The symbol –Inf represents positive infinity.
The symbol NaN represents a “NaN,” which is a floating-point value that represents an undefined value such as the result of the division $0/0$ .

The SAS language has 28 symbols that are used to represent special numerical values.

The symbol . represents a generic missing value.
The symbols .A–.Z and ._ are also missing values. Some applications use .I to represent positive infinity and use .M to represent negative infinity.

The following table shows how special numeric values in R are converted to SAS missing values:

The following table shows how SAS missing values are converted when data are transferred to R: