topic Re: when is 0.245 not 0.245? in SAS Programming

topic Re: when is 0.245 not 0.245? in SAS Programming https://communities.sas.com/t5/SAS-Programming/when-is-0-245-not-0-245/m-p/439125#M109540 <P>It's actually worse than you think.</P> <P>Run this:</P> <PRE><CODE class=" language-sas">data x; do X= .244 to .245 by .0001; Y=round(X,0.0001); output; end; format X Y 20.16; run; </CODE></PRE> <P>to obtain (on a PC):</P> <P> </P> <DIV class="branch"> <DIV> <DIV align="center"> <TABLE class="table" summary="Procedure Print: Data Set WORK.X" frame="box" rules="all" cellspacing="0" cellpadding="5"> <THEAD> <TR> <TH class="r header" scope="col">X</TH> <TH class="r header" scope="col">Y</TH> </TR> </THEAD> <TBODY> <TR> <TD class="r data">0.2440000000000000</TD> <TD class="r data">0.2440000000000000</TD> </TR> <TR> <TD class="r data">0.2441000000000000</TD> <TD class="r data">0.2441000000000000</TD> </TR> <TR> <TD class="r data">0.2442000000000000</TD> <TD class="r data">0.2442000000000000</TD> </TR> <TR> <TD class="r data">0.2443000000000000</TD> <TD class="r data">0.2443000000000000</TD> </TR> <TR> <TD class="r data">0.2444000000000000</TD> <TD class="r data">0.2444000000000000</TD> </TR> <TR> <TD class="r data">0.2444999999999900</TD> <TD class="r data">0.2445000000000000</TD> </TR> <TR> <TD class="r data">0.2445999999999900</TD> <TD class="r data">0.2446000000000000</TD> </TR> <TR> <TD class="r data">0.2446999999999900</TD> <TD class="r data">0.2447000000000000</TD> </TR> <TR> <TD class="r data">0.2447999999999900</TD> <TD class="r data">0.2448000000000000</TD> </TR> <TR> <TD class="r data">0.2448999999999900</TD> <TD class="r data">0.2449000000000000</TD> </TR> <TR> <TD class="r data">0.2449999999999900</TD> <TD class="r data">0.2450000000000000</TD> </TR> </TBODY> </TABLE> </DIV> </DIV> </DIV> <P>Read about numeric precision to know more.</P> <P>For example <A href="http://documentation.sas.com/?docsetId=lrcon&docsetTarget=p0ji1unv6thm0dn1gp4t01a1u0g6.htm&docsetVersion=9.4&locale=en" target="_self">here </A>or <A href="https://support.sas.com/documentation/cdl/en/lrcon/62955/HTML/default/viewer.htm#a000695157.htm" target="_self">here</A>.</P> <P> </P> <P> </P> <P> </P> Thu, 22 Feb 2018 00:21:08 GMT ChrisNZ 2018-02-22T00:21:08Z when is 0.245 not 0.245? https://communities.sas.com/t5/SAS-Programming/when-is-0-245-not-0-245/m-p/439056#M109511 <P style="font-weight: 400;"><STRONG>Hi everybody! </STRONG></P> <P style="font-weight: 400;"> </P> <P style="font-weight: 400;"><STRONG>I'm not getting this:</STRONG></P> <P style="font-weight: 400;"><STRONG>I created a data set via a do-loop, data x, below. </STRONG></P> <P style="font-weight: 400;"><STRONG>When I use a w.d format on the value that I 'see' in the output data(value), the value is rounded up(fvalue).</STRONG></P> <P style="font-weight: 400;"><STRONG>When I create a hard value for 0.245 and use the same w.d format, the value is rounded down(fvalue2).</STRONG></P> <P style="font-weight: 400;"><STRONG>Clearly, SAS does not see the raw value of 0.245 coming from the data as 0.245. </STRONG></P> <P style="font-weight: 400;"><STRONG>Question is why?</STRONG></P> <P style="font-weight: 400;"> </P> <P style="font-weight: 400;"><STRONG>Thanks for considering and I hope this is clear.</STRONG></P> <P style="font-weight: 400;"> </P> <P style="font-weight: 400;"><STRONG>Jon</STRONG></P> <P style="font-weight: 400;"> </P> <P style="font-weight: 400;"> </P> <P style="font-weight: 400;"><STRONG>data</STRONG><SPAN> </SPAN>x;</P> <P style="font-weight: 400;">do<SPAN> </SPAN>i=<SPAN> </SPAN><STRONG>.01</STRONG><SPAN> </SPAN>to<SPAN> </SPAN><STRONG>.99</STRONG><SPAN> </SPAN>by<SPAN> </SPAN><STRONG>.0001</STRONG>;</P> <P style="font-weight: 400;">value = i;</P> <P style="font-weight: 400;">output;</P> <P style="font-weight: 400;">end;</P> <P style="font-weight: 400;"><STRONG>run</STRONG>;</P> <P style="font-weight: 400;"> </P> <P style="font-weight: 400;"><STRONG>data</STRONG><SPAN> y</SPAN>;</P> <P style="font-weight: 400;">     <SPAN> </SPAN>set<SPAN> </SPAN>x;</P> <P style="font-weight: 400;">      fvalue=value;</P> <P style="font-weight: 400;">      fvalue2=<STRONG>0.2450</STRONG>;</P> <P style="font-weight: 400;">      rawvalue=fvalue2;</P> <P style="font-weight: 400;">     <SPAN> </SPAN>format<SPAN> </SPAN>fvalue fvalue2<SPAN> </SPAN><STRONG>8.2</STRONG>;</P> <P style="font-weight: 400;">     <SPAN> </SPAN>drop<SPAN> </SPAN>i;</P> <P style="font-weight: 400;"><STRONG>run</STRONG>;</P> <P style="font-weight: 400;"> </P> <P style="font-weight: 400;">                                    when is 0.245 not 0.245?                       </P> <P style="font-weight: 400;"> </P> <P style="font-weight: 400;">                    Obs    value      fvalue    rawvalue  fvalue2 </P> <P style="font-weight: 400;"> </P> <P style="font-weight: 400;">                      1      0.245        0.24       0.245          0.25</P> Wed, 21 Feb 2018 20:10:51 GMT https://communities.sas.com/t5/SAS-Programming/when-is-0-245-not-0-245/m-p/439056#M109511 JonnyDas 2018-02-21T20:10:51Z Re: when is 0.245 not 0.245? https://communities.sas.com/t5/SAS-Programming/when-is-0-245-not-0-245/m-p/439125#M109540 <P>It's actually worse than you think.</P> <P>Run this:</P> <PRE><CODE class=" language-sas">data x; do X= .244 to .245 by .0001; Y=round(X,0.0001); output; end; format X Y 20.16; run; </CODE></PRE> <P>to obtain (on a PC):</P> <P> </P> <DIV class="branch"> <DIV> <DIV align="center"> <TABLE class="table" summary="Procedure Print: Data Set WORK.X" frame="box" rules="all" cellspacing="0" cellpadding="5"> <THEAD> <TR> <TH class="r header" scope="col">X</TH> <TH class="r header" scope="col">Y</TH> </TR> </THEAD> <TBODY> <TR> <TD class="r data">0.2440000000000000</TD> <TD class="r data">0.2440000000000000</TD> </TR> <TR> <TD class="r data">0.2441000000000000</TD> <TD class="r data">0.2441000000000000</TD> </TR> <TR> <TD class="r data">0.2442000000000000</TD> <TD class="r data">0.2442000000000000</TD> </TR> <TR> <TD class="r data">0.2443000000000000</TD> <TD class="r data">0.2443000000000000</TD> </TR> <TR> <TD class="r data">0.2444000000000000</TD> <TD class="r data">0.2444000000000000</TD> </TR> <TR> <TD class="r data">0.2444999999999900</TD> <TD class="r data">0.2445000000000000</TD> </TR> <TR> <TD class="r data">0.2445999999999900</TD> <TD class="r data">0.2446000000000000</TD> </TR> <TR> <TD class="r data">0.2446999999999900</TD> <TD class="r data">0.2447000000000000</TD> </TR> <TR> <TD class="r data">0.2447999999999900</TD> <TD class="r data">0.2448000000000000</TD> </TR> <TR> <TD class="r data">0.2448999999999900</TD> <TD class="r data">0.2449000000000000</TD> </TR> <TR> <TD class="r data">0.2449999999999900</TD> <TD class="r data">0.2450000000000000</TD> </TR> </TBODY> </TABLE> </DIV> </DIV> </DIV> <P>Read about numeric precision to know more.</P> <P>For example <A href="http://documentation.sas.com/?docsetId=lrcon&docsetTarget=p0ji1unv6thm0dn1gp4t01a1u0g6.htm&docsetVersion=9.4&locale=en" target="_self">here </A>or <A href="https://support.sas.com/documentation/cdl/en/lrcon/62955/HTML/default/viewer.htm#a000695157.htm" target="_self">here</A>.</P> <P> </P> <P> </P> <P> </P> Thu, 22 Feb 2018 00:21:08 GMT https://communities.sas.com/t5/SAS-Programming/when-is-0-245-not-0-245/m-p/439125#M109540 ChrisNZ 2018-02-22T00:21:08Z