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 .
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:
Value in R |
SAS Missing Value |
---|---|
Inf |
.I |
–Inf |
.M |
NA |
. |
NaN |
. |
The following table shows how SAS missing values are converted when data are transferred to R:
SAS Missing Value |
Value in R |
---|---|
.I |
Inf |
.M |
–Inf |
All others |
NA |