m12 - creating sas data sets from raw data - 46 of 48.mht

sas的考试样题

      onmouseover=3D"window.status=3D'Display details on referencing a =
raw data file.'; "=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_6.htm">reference the =
raw=20
      data file</A></FONT> by creating a fileref. Just as you assign a =
libref by=20
      using a LIBNAME statement, you assign a fileref by using a =
FILENAME=20
      statement.
      <SCRIPT>writeInterface(docInfo1);</SCRIPT>
      =20
      <P><STRONG>Writing a DATA Step Program</STRONG><BR>The DATA =
statement=20
      indicates the beginning of the DATA step and <FONT =
color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on naming the data =
set.'; "=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_11.htm">names =
the SAS=20
      data set</A></FONT> to be created.=20
      <P>Next, you <FONT color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on specifying the =
raw data file.'; "=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_13.htm">specify the =
raw=20
      data file</A></FONT> by using the INFILE statement. The OBS=3D =
option in the=20
      INFILE statement enables you to process a specified number of=20
      observations.=20
      <P>This lesson teaches <FONT color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on listing the =
data set.'; "=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_14.htm">column =

      input</A></FONT>, the most common input style. Column input =
specifies=20
      actual column locations for data values. The INPUT statement <FONT =

      color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on describing the =
data.'; "=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_15.htm">describes =
the=20
      raw data</A></FONT> to be read and placed into the SAS data set.=20
      <P><STRONG>Submitting the Program</STRONG><BR>When you submit the =
program,=20
      you can use the OBS=3D option with the INFILE statement to <FONT=20
      color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on verifying the =
data.'; "=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_19.htm">verify =
that the=20
      correct data</A></FONT> is being read before reading the entire =
data file.=20

      <P>After you submit the program, view the log to <FONT =
color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on checking DATA =
step processing.'; "=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_22.htm">check =
the DATA=20
      step processing</A></FONT>. You can then <FONT color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on listing the =
data set.'; "=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_23.htm">list =
the data=20
      set</A></FONT> by using the PROC PRINT procedure.=20
      <P>Once you've checked the log and verified your data, you can =
modify the=20
      DATA step to <FONT color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on reading the =
entire raw data file.'; "=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_25.htm">read =
the entire=20
      raw data file</A></FONT> by removing the OBS=3D option from the =
INFILE=20
      statement.=20
      <P>If you are working with a raw data file that contains <FONT=20
      color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on invalid =
data.';"=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_27.htm">invalid=20
      data</A></FONT>, the DATA step continues to execute. Unlike syntax =
errors,=20
      invalid data errors do not cause SAS to stop processing a program. =
If you=20
      have a way to edit the invalid data, it's best to correct the =
problem and=20
      rerun the DATA step.=20
      <P><STRONG>Creating and Modifying Variables</STRONG><BR>To modify =
existing=20
      values or to create new variables, you can use an <FONT =
color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on the assignment =
statement.';"=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_30.htm">assignment=20
      statement</A></FONT> in any DATA step. Within assignment =
statements, you=20
      can specify any <A=20
      onmouseover=3D"window.status=3D'Display details on SAS =
expressions.';"=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_30.htm#express">SAS=20
      expression</A>.=20
      <P>You can use <FONT color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on arithmetic =
operators and date constants.';"=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_32.htm">date=20
      constants</A></FONT> to assign dates in assignment statements. You =
can=20
      also use SAS time constants and SAS datetime constants in =
assignment=20
      statements.=20
      <P><STRONG>Subsetting Data</STRONG><BR>To process only =
observations that=20
      meet a specified condition, use a <FONT color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on the subsetting =
IF statement.';"=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_35.htm">subsetting =
IF=20
      statement</A></FONT> in the DATA step.=20
      <P><STRONG>Reading Instream Data</STRONG><BR>To read instream data =
lines=20
      instead of an external file, use a <FONT color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on the CARDS =
statement.';"=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_37.htm">DATALINES=20
      statement</A></FONT> or a CARDS statement and enter data directly =
in your=20
      SAS program. Omit the RUN at the end of the DATA step.=20
      <P><STRONG>Creating a Raw Data File</STRONG><BR>When the goal of =
your SAS=20
      program is to create a raw data file and not a SAS data set, it is =

      inefficient to list a data set name in the DATA statement. Instead =
use the=20
      keyword <FONT color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on the _NULL_ =
keyword.';"=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_39.htm">_NULL_</A></F=
ONT>,=20
      which allows the power of the DATA step without actually creating =
a SAS=20
      data set. A SET statement specifies the SAS data set that you want =
to read=20
      from.=20
      <P>You can use the <FONT color=3D#003399><A=20
      onmouseover=3D"window.status=3D'Display details on the FILE =
statement.';"=20
      onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
      =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_40.htm">FILE</A></FON=
T>=20
      and <FONT color=3D#003399><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/m12/m12_41.htm">PUT</A></FONT=
>=20
      statements to write out the observations from a SAS data set to a =
raw data=20
      file just as you used the INFILE and INPUT statements to create a =
SAS data=20
      set. These two sets of statements work almost identically.=20
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    <TD align=3Dleft>
      <HR>
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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><STRONG>Reading Data from an External File or Reading Instream=20
      Data</STRONG>=20
      <BLOCKQUOTE>
        <DL>
          <DT><FONT color=3D#003399><A=20
          onmouseover=3D"window.status=3D'Display details on the LIBNAME =
statement.';"=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_4.htm"><STRONG>LIBNAM=
E</STRONG>=20
          <EM>libref</EM>=20
          =
<STRONG>'</STRONG><EM>SAS-data-library</EM><STRONG>';</STRONG></A>=20
          </FONT>
          <DT><FONT color=3D#003399><A=20
          onmouseover=3D"window.status=3D'Display details on the =
FILENAME statement.';"=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_6.htm"><STRONG>FILENA=
ME</STRONG>=20
          <EM>fileref</EM>=20
          <STRONG>'</STRONG><EM>filename</EM><STRONG>';</STRONG></A> =
</FONT>
          <DT><FONT color=3D#003399><A=20
          onmouseover=3D"window.status=3D'Display details on the DATA =
statement.';"=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_11.htm"><STRONG>DATA<=
/STRONG>=20
          <EM>SAS-data-set</EM>;</A> </FONT>
          <DD><FONT color=3D#003399><A=20
          onmouseover=3D"window.status=3D'Display details on the INFILE =
statement.';"=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20
          =
href=3D"http://www.sas.com/apps/OLTRN/59080/m12/m12_13.htm"><STRONG>INFIL=
E</STRONG>=20
          <EM>file-specification</EM></A> <A=20
          onmouseover=3D"window.status=3D'Display details on the OBS=3D =
option.';"=20
          onclick=3DsuggestBack() onmouseout=3D"window.status=3D''"=20