When you begin a SAS session, it's often convenient to set up your environment first. For example, you may want to

This chapter shows you how to define libraries, reference SAS files, and specify options for your SAS session. You also learn how to specify the form(s) of output to produce.

In this chapter, you learn to

Often the first step in setting up your SAS session is to define the libraries. In "Using the Programming Workspace" on page 18, you learned to use SAS windows to assign library names. You can also use programming statements to assign library names.

Remember that to reference a permanent SAS file, you

To define libraries, you can use a LIBNAME statement. You can store the LIBNAME statement with any SAS program so that the SAS data library is assigned each time the program is submitted.

The LIBNAME statement below assigns the libref Clinic to the SAS data library D:UsersQtrReports in the Windows environment.

libname clinic 'd:usersqtr
eports';

The table below gives some examples of physical names for SAS data libraries in various operating environments.

You can use multiple LIBNAME statements to assign as many librefs as needed.

After assigning a libref, it is a good idea to check the Log window to verify that the libref has been assigned successfully.

The LIBNAME statement is global, which means that the librefs remain in effect until you modify them, cancel them, or end your SAS session.

Therefore, the LIBNAME statement assigns the libref for the current SAS session only. Each time you begin a SAS session, you must assign a libref to each permanent SAS data library that contains files that you want to access in that session. (Remember that Work is the default libref for a temporary SAS data library.)

When you end your SAS session or delete a libref, SAS no longer has access to the files in the library. However, the contents of the library still exist on your operating system.

After you assign a libref, you specify it as the first element in the two-level name for a SAS file.

For example, in order for the PRINT procedure to read Clinic.Admit, you specify the two-level name of the file as follows:

proc print data=clinic.admit;
run;

You can use the LIBNAME statement to reference not only SAS files but also files that were created with other software products, such as database management systems.

SAS can read or write these files by using the appropriate engine for that file type. For some file types, you need to tell SAS which engine to use. For others, SAS automatically chooses the appropriate engine.

To indicate which engine to use, you specify the engine name in the LIBNAME statement, as shown below.

Interface library engines support read-only access to BMDP, OSIRIS, and SPSS files. With these engines, the physical filename that is associated with a libref is an actual filename, not a SAS library. This is an exception to the rules for librefs.

For example, the LIBNAME statement below specifies the libref Rptdata and the engine SPSS for the file G:Myspss.dat in the Windows operating environment.

libname rptdata spss 'g:myspss.dat';

For more information about interface library engines, see the SAS documentation for your operating environment.

If your site licenses SAS/ACCESS software, you can use the LIBNAME statement to access data that is stored in a DBMS file. The types of data you can access depend on your operating environment and on which SAS/ACCESS products you have licensed.

You've seen that you can assign librefs in order to access different types of data. If you completed "Using the Programming Workspace" on page 18, you know that after you have assigned a libref, you can view

The libraries that are currently defined for your SAS session are listed under Libraries in the Explorer window. To view details about a library, double-click Libraries (or select Libraries

View

Details

Information for each library (name, engine, type, host pathname, and date modified) is listed under Active Libraries.

To view the contents of a library, double-click the library name (or select the library name, and then select Open from the pop-up menu). A list of the files contained in the library is displayed. If you have the details feature turned on, then information about each file (name, size, type, description, and date modified) is also listed.

To display a file's contents in a windowing environment, you can double-click the filename (or select the filename, and then select Open from the pop-up menu). If you select a SAS data set (type Table or View), its contents are displayed in the VIEWTABLE window.

To display a file's properties, you can select the filename, and then select Properties from the pop-up menu.

If you have installed SAS/FSP software, you can type B or L in the selection field next to a data set name to browse the data set observation by observation or to list the contents of the data set, respectively. For more information, see the documentation for SAS/FSP.

If SAS/FSP is not installed, you can view the contents of a SAS data set by using the PRINT procedure (PROC PRINT). You can learn how to use PROC PRINT in Chapter 4, "Creating List Reports," on page 99.

You've learned how to use SAS windows to view the contents of a SAS library or of a SAS file. Alternatively, you can use the CONTENTS procedure to create SAS output that describes either of the following:

To view the contents of the entire Mylib library, you can submit the following PROC CONTENTS step:

proc contents data=mylib._all_ nods;
run;

The output from this step lists only the names, types, sizes, and modification dates for the SAS files in the Mylib library.

To view only the descriptor information for the Mylib.Admit data set, you can submit the following PROC CONTENTS step:

proc contents data=mylib.admit;
run;

The output from this step lists information for Mylib.Admit, including an alphabetic list of the variables in the data set.

In addition to PROC CONTENTS, you can also use PROC DATASETS to view the contents of a SAS library or a SAS data set. PROC DATASETS also enables you to perform a number of management tasks such as copying, deleting, or modifying SAS files.

PROC CONTENTS and PROC DATASETS overlap in terms of functionality. Generally, these two function the same:

PROC CONTENTS<options>;         PROC DATASETS<options>;

RUN;                                                              CONTENTS<options>;

                                                                QUIT;

The major difference between the CONTENTS procedure and the CONTENTS statement in PROC DATASETS is the default for libref in the DATA= option. For PROC CONTENTS, the default is either Work or User. For the CONTENTS statement, the default is the libref of the procedure input library. Notice also that PROC DATASETS is an interactive procedure that requires a QUIT statement rather than a RUN statement.

However, the options for the PROC CONTENTS statement and the CONTENTS statement in the DATASETS procedure are the same. For example, the following PROC steps produce essentially the same output (with minor formatting differences):

proc datasets;
   contents data=sasuser._all_ nods;
quit;

proc contents data=sasuser._all_ nods;
run;

As with PROC CONTENTS, you can also use PROC DATASETS to display the descriptor information for a specific SAS data set.

By default, PROC CONTENTS and PROC DATASETS list variables alphabetically. To list variable names in the order of their logical position (or creation order) in the data set, you can specify the VARNUM option in PROC CONTENTS or in the CONTENTS statement in PROC DATASETS.

For example, either of these programs creates output that includes the list of variables shown below:

proc datasets;
   contents data=sasuser.admit varnum;
quit;

proc contents data=sasuser.admit varnum;
run;

You use the Preferences window to set the result format(s) that you prefer. Your preferences are saved until you modify them, and they apply to all output that you create.

To open this window in desktop operating environments, select Tools

Options

Preferences

If you create HTML files, they are stored in the folder that you specify and are incrementally named sashtml.htm, sashtml1.htm, sashtml2.htm, and so on, throughout your SAS session.

Now look at the two choices for viewing HTML results: Internal browser and Preferred web browser. (These options appear in the Results tab only in the Windows operating environment.)

To view HTML output, you can choose between these two options in the Results tab of the Preferences window in the Windows operating environment:

The Results Viewer is displayed as a SAS window, as shown below.

If you select the preferred web browser, your HTML output is displayed in a separate browser that is independent of SAS. For example, the HTML output below is displayed in Microsoft Internet Explorer.

By default, page numbers and dates appear with output. The following OPTIONS statement suppresses the printing of both page numbers and the date and time in listing output.

options nonumber nodate;

In the following example, page numbers and the current date are not displayed in the PROC PRINT output. Page numbers are not displayed in the PROC FREQ output, either, but the date does appear at the top of the page that contains the PROC FREQ report.

options nonumber nodate;
proc print data=clinic.admit;
   var id sex age height weight;
   where age>=30;
run;
options date;
proc freq data=clinic.diabetes;

 
   where fastgluc>=300;
   tables sex;
run;

If you print page numbers, you can specify the beginning page number for your report by using the PAGENO= option. If you don't specify PAGENO=, output is numbered sequentially throughout your SAS session, starting with page 1.

In the following example, the output pages are numbered sequentially throughout the SAS session, beginning with number 3.

options nodate number pageno=3;
proc print data=hrd.funddrv;
run;

The PAGESIZE= option specifies how many lines each page of output contains. In the following example, each page of the output that the PRINT procedure produces contains 15 lines (including those used by the title, date, and so on).

options number pagesize=15;
proc print data=clinic.admit;
run;

The LINESIZE= option specifies the width of the print line for your procedure output and log. Observations that do not fit within the line size continue on a different line.

In the following example, the observations are longer than 64 characters, so the observations continue on a subsequent page.

options number linesize=64;
proc print data=flights.europe;
run;

If you use two-digit year values in your data lines, external files, or programming statements, you should consider another important system option, the YEARCUTOFF= option. This option specifies which 100-year span is used to interpret two-digit year values.

All versions of SAS represent dates correctly from 1582 A.D. to 20,000 A.D. (Leap years, century, and fourth-century adjustments are made automatically. Leap seconds are ignored, and SAS does not adjust for Daylight Savings Time.) However, you should be aware of the YEARCUTOFF= value to ensure that you are properly interpreting two-digit years in data lines.

As with other system options, you specify the YEARCUTOFF= option in the OPTIONS statement:

options yearcutoff=1925;

When a two-digit year value is read, SAS interprets it based on a 100-year span which starts with the YEARCUTOFF= value. The default value of YEARCUTOFF= is 1920.

However, you can override the default and change the value of YEARCUTOFF= to the first year of another 100-year span. For example, if you specify YEARCUTOFF=1950, then the 100-year span will be from 1950 to 2049.

options yearcutoff=1950;

Using YEARCUTOFF=1950, dates are interpreted as shown below:

Remember, the value of the YEARCUTOFF= system option affects only two-digit year values. A date value that contains a four-digit year value will be interpreted correctly even if it does not fall within the 100-year span set by the YEARCUTOFF=system option.

You can learn more about reading date values in Chapter 19, "Reading Date and Time Values," on page 581.

You've seen how to use SAS system options to change the appearance of output and interpret two-digit year values. You can also use the FIRSTOBS= and OBS= system options to specify the observations to process from SAS data sets.

You can specify either or both of these options as needed. That is, you can use

General form, FIRSTOBS= and OBS= options in an OPTIONS statement:

   FIRSTOBS=n

   OBS=n

where n is a positive integer. For FIRSTOBS=, n specifies the number of the first observation to process. For OBS=, n specifies the number of the last observation to process. By default,

FIRSTOBS=1. The default value for OBS= is MAX, which is the largest signed, four-byte integer that is representable in your operating environment.

The data set Sasuser.Heart contains 20 observations. If you specify FIRSTOBS=10, SAS reads the 10th observation of the data set first and reads through the last observation (for a total of 11 observations).

options firstobs=10;
proc print data=sasuser.heart;
run;

The PROC PRINT step produces the following output:

If you specify OBS=10 instead, SAS reads through the 10th observation, in this case for a total of 10 observations. (Notice that FIRSTOBS= has been reset to the default value.)

options firstobs=1 obs=10;
proc print data=sasuser.heart;
run;

Now the PROC PRINT step produces this output:

Combining FIRSTOBS= and OBS= processes observations in the middle of the data set. For example, the following program processes only observations 10 through 15, for a total of 6 observations:

options firstobs=10 obs=15;
proc print data=sasuser.heart;
run;

Here is the output:

To reset the number of the last observation to process, you can specify OBS=MAX in the OPTIONS statement.

options obs=max;

This instructs any subsequent SAS programs in the SAS session to process through the last observation in the data set being read.

As you saw above, using the FIRSTOBS= or OBS= system options determines the first or last observation, respectively, that is read for all steps for the duration of your current SAS session or until you change the setting. However, you may want to

To affect any single file, you can use FIRSTOBS= or OBS= as data set options instead of as system options. You specify the data set option in parentheses immediately following the input data set name.

As shown in the last example above, this program processes only observations 10 through 15, for a total of 6 observations:

options firstobs=10 obs=15;
proc print data=sasuser.heart;
run;

You can create the same output by specifying FIRSTOBS= and OBS= as data set options, as follows. The data set options override the system options for this instance only.

options firstobs=10 obs=15;
proc print data=sasuser.heart(firstobs=10 obs=15);
run;

To specify FIRSTOBS= or OBS= for this program only, you could omit the OPTIONS statement altogether and simply use the data set options.

You can also set system options by using the SAS System Options window. However, you cannot store the option settings in your SAS programs as you can when you use the OPTIONS statement.

To view the SAS System Options window, select Tools

Options

System

To change an option:

For example, the SAS System Options window above shows options for the SAS log and procedure output subgroup under the group Log and procedure output control.

To locate an option in the SAS System Options window:

The SAS System Options window expands to the appropriate option subgroup. All subgroup options also appear, and the option that you located is highlighted.