SAS Chapter 13: Creating Samples And Indexes

Automatically during compilation of the DATA step.

Automatically during execution of the DATA step.

During compilation of the DATA step, by program statements.

During execution of the DATA step, by program statements.

data sample; set sasuser.sale2000 point=thisone nobs=totnum; output; stop; run;

data sample; do thisone=100 to totnum by 100; set sasuser.sale2000 point=thisone nobs=totnum; output; end; stop; run;

data sample; do thisone=100 to 1000 by 100; set sasuser.sale2000 point=thisone; output; end; stop; run;

data sample; do thisone=100 to totnum by 100; set sasuser.sale2000 point=thisone nobs=totnum; end; run;

Ceil(ranuni(50))

Ranuni(50)

Ceil(ranuni(0)*50)

Ceil(ranuni(0))*50

Is an optional file that is associated with a data set.

Provides direct access to specific observations of a data set, based on the value of one or more key variables.

Can be classified as simple or composite, either of which can consist of unique values.

All of the above

options msglevel=i; data flights index=(Fromto=origin dest); set sasuser.revenue; run;

options msglevel=n; data flights (index=(Fromto=origin dest)); set sasuser.revenue; run;

options msglevel=i; data flights (index=(Fromto=(origin dest))); set sasuser.revenue; run;

options msglevel=n; data flights (index=Fromto); set sasuser.revenue; run;

When you add observations to a data set, the index(es) are automatically updated with additional value/identifier pairs.

When you rename a variable that is used as the key variable in a simple index, you must re-create the index.

When you delete a data set, the index file remains until you delete it as well.

When you copy a data set with the COPY statement, you must also copy the index file in another step.

PROC DATASETS.

PROC SQL.

The DATA step with the INDEX= option, to rebuild the data set.

Any of the above

proc sql; create index origin on revenue(origin); quit;

proc sql; modify revenue; index=origin; quit;

proc sql data=revenue; create index origin; quit;

proc sql; index=origin on revenue; quit;

PROC COPY or the COPY statement in PROC DATASETS.

PROC CONTENTS or the CONTENTS statement in PROC DATASETS.

The MSGLEVEL= system option and a PROC PRINT step.

Any of the above

proc print data=sasuser.revenue; where flightid ne 'IA11200'; run;

data someflights; set sasuser.revenue; where flightid > 'IA11200'; run;

data someflights; set sasuser.revenue; if flightid > 'IA11200'; run;

proc print data=sasuser.revenue; where origin='RDU' or flightid='IA03400'; run;