问题描述
我有一个 SAS 项目 (EGv7.1),它允许用户在第一行指定一个值.然后,根据指定的值调用其他进程.其中之一是分配了一些其他宏变量.以下是我所拥有的,它似乎不起作用.我真的需要 let 语句在序列中排在第一位,但除此之外,我愿意接受更改.有什么建议吗?
I have a SAS project (EGv7.1) that allows the user to specify a value on the first line. Then, other processes are invoked based on the value specified. One of these is that some other macro variables are assigned. Below is what I have, and it does not seem to be working. I really need the let statement to be first in the sequence, but besides that I am open to changes. Any suggestions?
%let number=8;
%macro my_function();
%if &number=8 %then
%do;
%let number_text=eight;
%let number_text_2=equal to eight;
%end;
%if &number>8 %then
%do;
%let number_text=not eight;
%let number_text_2=greater then eight;
%end;
%if &number<8 %then
%do;
%let number_text=not eight;
%let number_text_2=less than eight;
%end;
%mend my_function;
%my_function();
%put =================&number==================;
%put ===========The number is &number_text.=============;
%put =======Furthermore, the number is &number_text_2.========;
推荐答案
当您在宏内使用 %let
语句时,变量默认为局部作用域.也就是说,它们只存在于宏内部.为了解决这个问题,在宏中添加一个 %global
语句.
When you use %let
statements inside of a macro, the variables default to local scope. That is, they only exist inside the macro. To remedy that add a %global
statement inside the macro.
%let number = 8;
%macro my_function();
%global number_text number_text_2;
%if %sysevalf(&number = 8) %then
%do;
%let number_text = eight;
%let number_text_2 = equal to eight;
%end;
%else %if %sysevalf(&number > 8) %then
%do;
%let number_text = not eight;
%let number_text_2 = greater than eight;
%end;
%else %if %sysevalf(&number < 8) %then
%do;
%let number_text = not eight;
%let number_text_2 = less than eight;
%end;
%mend my_function;
%my_function();
这告诉 SAS 宏变量 number_text
和 number_text_2
应该可以在宏之外访问,这应该可以解决您的问题.
This tells SAS that the macro variables number_text
and number_text_2
should be accessible outside of the macro, which should fix your problem.
我还建议将 %else
添加到您的 %if
中.这确保了每个条件只在它前面的条件为假时才被评估.如果没有 %else
,则每次都会评估每个条件.
I also recommend adding %else
to your %if
s. This ensures that each condition is only evaluated if the one preceding it is false. Without %else
, each condition is evaluated every time.
正如@DomPazz 提到的,在评估数字条件时使用 %sysevalf()
是个好主意.
As @DomPazz mentioned, it's a good idea to use %sysevalf()
when evaluating numeric conditions.
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