Chapter 6: Creating SAS Data Sets from External Files
Correct answer: a
You assign a fileref
by using a FILENAME statement in the same way that you assign a libref
by using a LIBNAME statement.
Correct answer: d
Like LIBNAME statements,
FILENAME statements are global; they remain in effect until changed
or canceled, or until the SAS session ends.
Correct answer: b
You use an INFILE statement
to specify the raw data file to be read. You can specify a fileref
or an actual filename (in quotation marks). The OBS= option in the
INFILE statement enables you to process only records 1 through n.
Correct answer: d
The keyword _NULL_ in
the DATA statement enables you to use the power of the DATA step without
actually creating a SAS data set. You use FILE and PUT statements
to write observations from a SAS data set to a raw data file. The
FILE statement specifies the raw data file, and the PUT statement
describes the lines to write to the raw data file. The filename and
location that are specified in the FILE statement must be enclosed
in quotation marks.
Correct answer: b
Column input is appropriate
only in some situations. When you use column input, your data must
be standard character or numeric values, and they must be in fixed
fields. That is, values for a particular variable must be in the same
location in all records.
Correct answer: a
The INPUT statement
creates a variable using the name that you assign to each field. Therefore,
when you write an INPUT statement, you need to specify the variable
names exactly as you want them to appear in the SAS data set.
Correct answer: b
You can use column input
to read fields in any order. You must specify the variable name, identify
character variables with a $, and specify the correct starting and
ending column for each field.
Correct answer: c
To redefine the values
of the variable Income in an assignment statement, you specify the
variable name on the left side of the equal sign and an appropriate
expression including the variable name on the right side of the equal
sign.
Correct answer: d
To read instream data,
you specify a DATALINES statement and data lines, followed by a null
statement (single semicolon) to indicate the end of the input data.
Program a. contains no DATALINES statement, and the INPUT statement
does not specify the fields to read. Program b. contains no data lines,
and the INPUT statement in Program c. does not specify the necessary
dollar signs for the character variables Country and Vehicle.
Correct answer: c
To subset data, you
can use a subsetting IF statement in any DATA step to process only
those observations that meet a specified condition. Because Sex is
a character variable, the value F must
be enclosed in quotation marks and must be in the same case as in
the data set.