因为最近开始使用SAS，顺便考SAS BASE 不过太久没碰的下场就是好多东西都忘记了.... 想请问以下几个题目，希望强者能够提供一些见解(跪) 1. data work.test; capacity = 150; if 100 le capacity le 200 then airplanetype = 'large' and staff = 10; else airplanetype = 'small' and staff = 5; run; 题目希望data set 长成如下，上面这个是错的，只是我不确定错在哪里 capacity airplanetype staff 150 large 10 就题目而言，是因为else 少了一个if吗？ 另外就是if-then的语法里面，如果有假设三个if-then的时候 一般都是打成if-then else if-then else (最後这个就不用加上？） 2.submit following libname sasdata ' ' data allobs; set sasdata.banks; capital = 0; do year = 2000 to 2020 by 5; capital+((capital+2000)*rate); output; end; run; if sasdata.banks has five observation，how many observations will the ALLOBS contain? Ans:25 这个我就掉到五里雾里面了.... 另外一个疑问是，output的使用时机，虽然讲义上面是写prevent continuous looping， 但感觉有一点抽象，另外是不是用了output，後面一定要用stop; ? 3.submit following data work.XXX set work.people (in = inemp) work.money (in = insal); if insal = inemp; run; work.people has 5 observations, and work.money has 7 observations How many obs contain in work.XXXX? Ans: 0 因为这应该是一个concatenating，为什麽不是12个 obs? 4. 在从外部抓资料的时候 input style $ @; style是一个variable的名字，但後面的＠代表什麽意义？ 因为我看到的都是input @4 style $2.;类似这种的，但＠在後面的有特别意义吗？ 5. data work.total; infile where end = eof; input name $ salary; total + salary; (if statement) run; which statement would write the last observation to the output data set? Ans: if eof = 1; 不太了解题意，最後想问一下if如果再没有then的搭配下，跟where statement有什麽 差别呢？ 我想对大家来说这些都是很简单的问题，还请大家不赐吝教，感恩 -- "When someone sees you as you really are and wants to be with you ,that's powerful." --

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