跟crakman做sas base认证试题（25）

shiyiming

From crackman's blog on Baidu


               
                <p><font size="4">25.Given the following code:<br>
<br>
proc print data=SASHELP.CLASS(firstobs=5 obs=15);<br>
&nbsp;&nbsp;&nbsp;  where Sex='M';<br>
run; <br>
<br>
How many observations will be displayed? </font></p>
<p><font size="4">&nbsp;&nbsp;&nbsp;&nbsp;  A. 11<br>
&nbsp;&nbsp;&nbsp;&nbsp;  B. 15<br>
&nbsp;&nbsp;&nbsp;&nbsp;  C. 10 or fewer <br>
&nbsp;&nbsp;&nbsp;&nbsp;  D. 11 or fewer </font></p>
<p><font size="4">Answer: D<br>
本文属于博客：</font><a href="http://hi.baidu.com/crack_man/home"><font size="4"><!-- m --><a class="postlink" href="http://hi.baidu.com/crack_man/home">http://hi.baidu.com/crack_man/home</a><!-- m --></font></a><font size="4"> 版权归作者所有，欢迎转载！如有转载，请务必注明出处！未经本文作者同意不得用于商业应用。</font></p>
<p><font size="4">本题考察的是firstobs以及obs两个参数的作用。<br>
FIRSTOBS：确定读取观测的起始序列号，obs是确定读取观测终止时的序列号。也就是从第五个观测开始，到第15个观测时结束。<br>
从第5和第15之间的数据有11个，根据where的筛选，所以答案为D。<br>
看看外文文献的解释：<br>
Use the FIRSTOBS= and OBS= options together to process a set of observations from the middle of a data set. For example, this statement processes only observations 1000 through 1100: <br>
options firstobs=1000 obs=1100;</font></p>
<p> </p> <a href="http://hi.baidu.com/crack%5Fman/blog/item/bc7d9755d7ed473443a75b03.html">阅读全文</a>
               
                <br/><b>类别：</b><a href="http://hi.baidu.com/crack%5Fman/blog/category/%B8%FAcrackman%D7%F6sas%20base%C8%CF%D6%A4%CA%D4%CC%E2">跟crackman做sas base认证试题</a>&nbsp;<a href="http://hi.baidu.com/crack%5Fman/blog/item/bc7d9755d7ed473443a75b03.html#comment">查看评论</a>