m22 - understanding data step processing - 45 of 47.mht

sas的考试样题

      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_8.htm">written =
to the=20
      new data set</A> as an observation. The DATA step executes once =
for each=20
      record in the input file, unless otherwise directed.=20
      <P><STRONG>Diagnosing Errors in the Compilation =
Phase</STRONG><BR>Missing=20
      semicolons, misspelled keywords, and invalid options will cause <A =

      onmouseover=3D"window.status=3D'Display details on syntax =
errors.'; "=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_30.htm">syntax =

      errors</A> in the compilation phase. Detected errors are =
underlined and=20
      are identified with a number and message in the log. If SAS can =
interpret=20
      a syntax error, the DATA step compiles and executes; if SAS cannot =

      interpret the error, the DATA step compiles but doesn't execute.=20
      <P><STRONG>Diagnosing Errors</STRONG><STRONG> in the Execution=20
      Phase</STRONG><BR>Illegal mathematical operations or processing a=20
      character variable as numeric will cause <A=20
      onmouseover=3D"window.status=3D'Display details on execution-time =
errors.'; "=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_31.htm">errors =
in the=20
      execution phase</A>. Depending on the type of error, the log might =
show a=20
      warning and might include invalid data from the program data =
vector, and=20
      the DATA step either stops or continues.=20
      <P><STRONG>Testing Your Programs</STRONG><BR>To detect common =
errors and=20
      save development time, compile and execute your program without =
creating=20
      observations. Specify the <A=20
      onmouseover=3D"window.status=3D'Display details on the keyword =
_NULL_.'"=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      =
href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_37.htm">keyword=20
      _NULL_</A> as the data set name to view compilation or execution =
errors=20
      without creating a data set. Or use the OBS=3D option in the =
INFILE=20
      statement to limit the number of observations that are read or =
created=20
      during the DATA step. You can also use the <A=20
      onmouseover=3D"window.status=3D'Display details on the PUT =
statement.'"=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_40.htm">PUT=20
      statement</A> to examine variable values and to generate your own =
message=20
      in the log. </P></TD></TR></TBODY></TABLE><!-- InstanceEndEditable =
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<P><!-- InstanceBeginEditable name=3D"syntax" -->
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    <TD><STRONG><A name=3DSyntax>Syntax</A></STRONG>=20
      <P><EM>To go to the page where a statement or option was =
presented, select=20
      a link.</EM>=20
      <P>
      <BLOCKQUOTE>
        <DL>
          <DT><FONT color=3D#003399><A=20
          onmouseover=3D"window.status=3D'Display information on the =
DATA statement.'"=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_2.htm"><STRONG>DATA</=
STRONG></A><A=20
          onmouseover=3D"window.status=3D'Display information on the =
keyword _NULL_.'"=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_37.htm">=20
          &lt;_NULL_|</A><A=20
          onmouseover=3D"window.status=3D'Display information on the =
DATA statement.';"=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_2.htm"><EM>SAS-data-s=
et</EM>&gt;<STRONG>;</STRONG></A></FONT>=20

          <DD><FONT color=3D#003399><STRONG><A=20
          onmouseover=3D"window.status=3D'Display information on the =
INFILE statement.'; "=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_2.htm">INFILE</A></ST=
RONG><A=20
          onmouseover=3D"window.status=3D'Display information on the =
INFILE statement.'; "=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_2.htm">=20
          <EM>file-specification </EM></A><A=20
          onmouseover=3D"window.status=3D'Display information on the =
OBS=3D system option.'"=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_37.htm"><STRONG>OBS=3D=
</STRONG><EM>n</EM></A><A=20
          onmouseover=3D"window.status=3D'Display information on the =
INFILE statement.'; "=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_2.htm"><STRONG>;</STR=
ONG></A></FONT>=20

          <DD><FONT color=3D#003399><NOBR><A=20
          onmouseover=3D"window.status=3D'Display information on the =
INPUT statement.'; "=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_5.htm"><STRONG>INPUT<=
/STRONG><EM>=20
          variable-1 informat-1 =
input-pointer-control-1</EM></A></NOBR></FONT>=20
          <DD><NOBR>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<FONT =
color=3D#003399>=20
          <A=20
          onmouseover=3D"window.status=3D'Display information on the =
INPUT statement.'; "=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_5.htm"><EM>&lt; . .=20
          .variable-n informat-n <BR></EM></A></FONT>&nbsp; &nbsp; =
&nbsp; &nbsp;=20
          &nbsp;&nbsp;<FONT color=3D#003399> <A=20
          onmouseover=3D"window.status=3D'Display information on the =
INPUT statement.'; "=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_5.htm"><EM>input-poin=
ter-control-n&gt;</EM><STRONG>;</STRONG></A></FONT></NOBR>=20

          <DD><FONT color=3D#003399></FONT>
          <DD><FONT color=3D#003399><A=20
          onmouseover=3D"window.status=3D'Display information on the PUT =
statement.'"=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m22/m22_40.htm"><STRONG>PUT</=
STRONG>=20
          <EM>specification(s)</EM><STRONG>;</STRONG></A></FONT>=20
          <DT><FONT color=3D#003399><STRONG>RUN</STRONG>;</FONT>=20
      </DT></DL></BLOCKQUOTE></TD></TR></TBODY></TABLE>
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    <TD align=3Dleft><STRONG><A name=3DSample>Sample =
Programs</A></STRONG> <PRE><FONT color=3D#003399>     data =
perm.update;</FONT>
<FONT color=3D#003399>        infile invent;</FONT>
<FONT color=3D#003399>        input Item $ 1-13 IDnum $ 15-19</FONT>
<FONT color=3D#003399>              InStock 21-22 BackOrd 24-25;</FONT>
<FONT color=3D#003399>        Total=3Dinstock+backord;</FONT>
<FONT color=3D#003399>     run;</FONT>

     <FONT color=3D#003399>data work.test;</FONT>
        <FONT color=3D#003399>infile loan;</FONT>
        <FONT color=3D#003399>input Code $ 1 Amount 3-10;</FONT>
        <FONT color=3D#003399>if code=3D'1' then =
type=3D'variable';</FONT>
        <FONT color=3D#003399>else if code=3D'2' then =
type=3D'fixed';</FONT>
        <FONT color=3D#003399>else put 'MY NOTE: invalid value: '</FONT>
             <FONT color=3D#003399>code=3D;</FONT>
     <FONT color=3D#003399>run;</FONT></PRE>
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<P><!-- InstanceBeginEditable name=3D"pointstoremember" -->
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    <TD align=3Dleft><STRONG><A name=3DPoints>Points to =
Remember</A></STRONG><BR>
      <UL>
        <LI>Making, diagnosing, and resolving errors is part of the =
process of=20
        writing programs. However, checking for common errors will save =
you time=20
        and trouble. Make sure that<BR><BR>
        <UL>
          <LI>each SAS statement ends with a semicolon=20
          <LI>filenames are spelled correctly=20
          <LI>keywords are spelled correctly.<BR><BR></LI></UL>
        <LI>In SAS output, missing numeric values are represented by =
periods,=20
        and missing character values are left blank.<BR><BR>
        <LI>The order in which variables are defined in the DATA step =
determines=20
        the order in which the variables are stored in the data =
set.<BR><BR>
        <LI>Standard character values can include numbers, but numeric =
values=20
        cannot include characters. =
</LI></UL></TD></TR></TBODY></TABLE><!-- InstanceEndEditable =
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    <TD width=3D14><IMG height=3D7 alt=3D""=20
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