SAS如何有效地创建具有相应值的变量 [英] SAS how to create variable with corresponding values efficiently

问题描述

我正在尝试完成以下操作.

I am trying to complete the following.

变量字母具有三个值(a，b，c).我想创建一个变量Letter_2，其值对应于Letter的值，即(1、2、3).

Variable Letter has three values (a, b, c). I would like to create a variable Letter_2 with values corresponding to the values of Letter, namely (1, 2, 3).

我知道我可以使用三个IF Then语句来做到这一点.

I know I can do this using three IF Then statements.

if Letter='a' then Letter_2='1';
if Letter='b' then Letter_2='2';
if Letter='c' then Letter_2='3';

假设我有15个变量Letter值和15个对应的替换值.有没有一种方法可以有效地做到这一点，而无需键入相同的If If语句15次?

Suppose I have 15 values for the variable Letter, and 15 corresponding values for the replacement. Is there a way to do it efficiently without typing the same If Then statement 15 times?

我是SAS新手.任何线索将不胜感激.

I am new to SAS. Any clue will be appreciated.

丽莎

推荐答案

看起来像是FORMAT的应用程序.

Looks like an application for a FORMAT.

首先定义格式.

proc format ;
  value $lookup 'a'='1' 'b'='2' 'c'='3' ;
run;

然后使用它重新编码您的变量.

Then use it to re-code your variable.

data want;
  set have;
  letter2 = put(letter,$lookup.);
run;

或者也许您可以使用两个临时数组和 WHICHC()函数?

Or perhaps you could use two temporary arrays and the WHICHC() function?

data have;
  input letter $10. ;
cards;
car
apple
box
;;;;

data want ;
  set have ;
  array from (3) $10 _temporary_ ('apple','box','car');
  array to (3) $10 _temporary_ ('first','second','third');
  if whichc(letter,of from(*)) then 
    letter_2 = to(whichc(letter,of from(*)))
  ;
run;

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