| SAS Companion for the OpenVMS Environment |
The default
length of numeric variables in SAS data sets is 8
bytes. (You can control the length of SAS numeric variables with the LENGTH
statement in the DATA step.) In the SAS System under OpenVMS VAX, the VAX
data type of numeric values with a length of 8 bytes is D_FLOATING. The precision
of this type of floating-point value is 16 decimal digits. For more information
about the representation of the D_FLOATING VAX data type, refer to Architecture Reference Manual for
VAX.
Significant Digits and Largest Integer by Length for SAS Variables in the VAX Environment
specifies the significant digits and largest integers that can be stored in
SAS numeric variables.
Significant Digits and Largest Integer by Length for SAS Variables in the VAX Environment
|
Length in Bytes |
Significant Digits Retained |
Largest Integer Represented Exactly |
|
2 |
2 |
256 |
|
3 |
4 |
65,536 |
|
4 |
7 |
16,777,316 |
|
5 |
9 |
4,294,967,296 |
|
6 |
12 |
1,099,511,627,776 |
|
7 |
14 |
281,474,946,710,656 |
|
8 |
16 |
72,057,594,037,927,936 |
For example, if you know that the
values of a numeric
variable are between 0 and 100, you can use a length of 2
bytes to store the number. This saves space in your data
set. The following is an example:
data mydata;
length num 2;
input num;
run;
Note:
Dummy
variables (those whose only purpose is to
hold a value of 0 or 1) can be stored in a variable whose length is 2 bytes. ![[cautend]](../common/images/cautend.gif)
- CAUTION:
- Only use the 2-byte limit for variables
whose values are small, preferably integers.
If the value of a variable becomes large or has many significant digits, you
may lose precision during arithmetic calculations if the length is only 2
bytes.
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
