📄 m22 - understanding data step processing - 46 of 47.mht
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DATA=20
step statement.<!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dc name=3Dques3> </TD>
<TD> <EM>c.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q3c" -->once for each =
record=20
in the input file.<!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dd name=3Dques3> </TD>
<TD> <EM>d.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q3d" -->once for each =
variable in the input=20
file.<!-- InstanceEndEditable --></TD></TR></TBODY></TABLE>
<P></P>
<LI><!-- InstanceBeginEditable name=3D"q4text" -->At the =
beginning of the=20
execution phase, the value of <CODE>_N_</CODE> is <EM>1</EM>, =
the value=20
of <CODE>_ERROR_</CODE> is <EM>0</EM>, and the values of the =
remaining=20
variables are set to:<!-- InstanceEndEditable -->=20
<P>
<TABLE border=3D0>
<TBODY>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Da name=3Dques4> </TD>
<TD> <EM>a.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q4a" =
--><EM>0</EM><!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Db name=3Dques4> </TD>
<TD> <EM>b.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q4b" =
--><EM>1</EM><!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dc name=3Dques4> </TD>
<TD> <EM>c.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q4c" -->undefined<!-- =
InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dd name=3Dques4> </TD>
<TD> <EM>d.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q4d" -->missing<!-- =
InstanceEndEditable --></TD></TR></TBODY></TABLE>
<P></P>
<LI><!-- InstanceBeginEditable name=3D"q5text" -->Suppose you =
run a=20
program that causes three DATA step errors. What is the value of =
the=20
automatic variable <CODE>_ERROR_</CODE> when the observation =
that=20
contains the third error is processed?<!-- InstanceEndEditable =
-->=20
<P>
<TABLE border=3D0>
<TBODY>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Da name=3Dques5> </TD>
<TD> <EM>a.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q5a" =
--><EM>0</EM><!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Db name=3Dques5> </TD>
<TD> <EM>b.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q5b" =
--><EM>1</EM><!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dc name=3Dques5> </TD>
<TD> <EM>c.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q5c" =
--><EM>2</EM><!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dd name=3Dques5> </TD>
<TD> <EM>d.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q5d" =
--><EM>3</EM><!-- InstanceEndEditable --></TD></TR></TBODY></TABLE>
<P></P>
<LI><!-- InstanceBeginEditable name=3D"q6text" -->At the end of =
the DATA=20
step, three actions occur. The first two are:=20
<UL>
<LI>The values in the program data vector are written to the =
data set=20
as an observation.=20
<LI>Control returns to the top of the DATA step. =
</LI></UL>What is the=20
third action?<!-- InstanceEndEditable -->=20
<P>
<TABLE border=3D0>
<TBODY>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Da name=3Dques6> </TD>
<TD> <EM>a.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q6a" -->The automatic =
variable <CODE>_N_</CODE> is incremented by one.<!-- =
InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Db name=3Dques6> </TD>
<TD> <EM>b.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q6b" -->The DATA step =
stops=20
execution.<!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dc name=3Dques6> </TD>
<TD> <EM>c.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q6c" -->The =
descriptor=20
portion of the data set is=20
written.<!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dd name=3Dques6> </TD>
<TD> <EM>d.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q6d" -->The values of =
variables in the program data vector are re-set to =
missing.<!-- InstanceEndEditable --></TD></TR></TBODY></TABLE>
<P></P>
<LI><!-- InstanceBeginEditable name=3D"q7text" -->Look carefully =
at the=20
DATA step shown below. Based on the INPUT statement, in what =
order will=20
the variables be stored in the new data set? <PRE><FONT =
color=3D#003399>data perm.update;
infile invent;
input IDnum $ 15-19 Item $ 1-13 Instock 21-22
BackOrd 24-25;
Total=3Dinstock+backord;
run;</FONT></PRE><!-- InstanceEndEditable -->
<P>
<TABLE border=3D0>
<TBODY>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Da name=3Dques7> </TD>
<TD> <EM>a.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q7a" --><TT>IDnum =
Item=20
InStock BackOrd Total</TT><!-- InstanceEndEditable =
--></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Db name=3Dques7> </TD>
<TD> <EM>b.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q7b" --><TT>Item =
IDnum=20
InStock BackOrd Total</TT><!-- InstanceEndEditable =
--></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dc name=3Dques7> </TD>
<TD> <EM>c.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q7c" --><TT>Total =
IDnum Item=20
InStock BackOrd</TT><!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dd name=3Dques7> </TD>
<TD> <EM>d.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q7d" --><TT>Total =
Item IDnum=20
InStock=20
BackOrd</TT><!-- InstanceEndEditable =
--></TD></TR></TBODY></TABLE>
<P></P>
<LI><!-- InstanceBeginEditable name=3D"q8text" -->If SAS cannot =
interpret=20
syntax errors, then...<!-- InstanceEndEditable -->=20
<P>
<TABLE border=3D0>
<TBODY>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Da name=3Dques8> </TD>
<TD> <EM>a.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q8a" -->data set =
variables=20
will contain missing values.<!-- InstanceEndEditable =
--></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Db name=3Dques8> </TD>
<TD> <EM>b.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q8b" -->the DATA step =
does=20
not compile.<!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dc name=3Dques8> </TD>
<TD> <EM>c.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q8c" -->the DATA step =
still=20
compiles, but it does not=20
execute.<!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dd name=3Dques8> </TD>
<TD> <EM>d.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q8d" -->the DATA step =
still=20
compiles and=20
executes.<!-- InstanceEndEditable --></TD></TR></TBODY></TABLE>
<P></P>
<LI><!-- InstanceBeginEditable name=3D"q9text" -->What is wrong =
with this=20
program? <PRE><FONT color=3D#003399>data perm.update;
infile invent
input Item $ 1-13 IDnum $ 15-19 Instock 21-22
BackOrd 24-25;
total=3Dinstock+backord;
run;</FONT></PRE><!-- InstanceEndEditable -->
<P>
<TABLE border=3D0>
<TBODY>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Da name=3Dques9> </TD>
<TD> <EM>a.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q9a" -->missing =
semicolon on=20
second line<!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Db name=3Dques9> </TD>
<TD> <EM>b.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q9b" -->missing =
semicolon on=20
third line<!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dc name=3Dques9> </TD>
<TD> <EM>c.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q9c" -->incorrect =
order of=20
variables<!-- InstanceEndEditable --></TD></TR>
<TR vAlign=3Dtop>
<TD><INPUT type=3Dradio value=3Dd name=3Dques9> </TD>
<TD> <EM>d.</EM> </TD>
<TD><!-- InstanceBeginEditable name=3D"q9d" -->incorrect =
variable=20
type<!-- InstanceEndEditable --></TD></TR></TBODY></TABLE>
<P></P>
<LI><!-- InstanceBeginEditable name=3D"q10text" -->Look =
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