动态宏变量访问SAS [英] Dynamic macro variable access SAS

问题描述

我已经使用调用symputx创建了一个宏变量Item 1到Item N的列表，现在我想将它们传输到另一个数据步骤中的数组，以便数组中的点1获得Item1，点2获得Item2，依此类推.

I've used call symputx to create a list of macro variables Item 1 to Item N and now I want to transfer them to an array in another datastep so that spot 1 in the array gets Item1, spot 2 gets Item2, etc.

    do j=1 to &num_OR;
    rulesUsed{j}=&&Item&j;
    end;

我读到，双与号语法是引用此类宏变量的方式，但我不断遇到各种错误.我敢肯定有一个简单的方法可以解决这个问题，但是我是SAS的新手，在搜索中没有我读过的文档中提到这种确切类型的问题.

I read that the double ampersand syntax is the way to reference macro variables like this but I keep getting all sorts of errors. I'm sure there's a simple way around this but I'm new to SAS and no document I've read through that's come up in searches mentions this exact type of problem.

推荐答案

简短的答案是:通常不要这样做.宏变量不是存储数据的好方法，而且几乎总是有更好的方法.

The short answer is: don't do this, in general. Macro variables aren't a great way to store data, and there's nearly always a better way.

但是，如果需要，这里的问题是宏变量不能使用数据步长变量.

But if you need to, your issue here is that the macro variable can't use the data step variable.

 do j=1 to &num_OR;
    rulesUsed{j}=&&Item&j;
 end;

j是数据步变量，而不是宏变量，因此不是&j.您需要:

j is a data step variable, not a macro variable, and so it's not &j. You need to either:

1-使用symget检索宏变量.这是一个数据步骤函数，它使用常规的数据步骤字符参数(因此是变量，"字符串等)，并返回具有该名称的宏变量.所以

1 - Use symget to retrieve the macro variable. That's a data step function that takes a normal data step character argument (so a variable, a " " string, etc.) and returns the macro variable with that name. So

rulesUsed[j] = symget(cats("item",j));

2-使用宏循环检索宏变量.

2 - Use a macro loop to retrieve the macro variable.

%do j = 1 %to &num_or;
  rulesUsed[&j.] = &&item&j;
%end;

这两种方法都可以正常工作.

Either of these methods work fine.

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