sas retain语句 SAS retain语句: ①是SAS编程中用于在数据步(DATA step)中保留变量值的语句; ②通常在处理数据时,数据步每执行一次迭代,SAS会自动将由INPUT或赋值语句创建的变量值重置为缺失值,但使用RETAIN语句可以防止这种情况发生,使变量保留上一次迭代的值; ③基本语法是“RETAIN variable-list;”或“RETAIN ...
The data step is the most frequently used programming process in the SAS System. As programmers we should be veryfamiliar with it. However, sometimes we write a piece of code, but the output is not our expectation. Is our code incorrect or are there mysteries inside the data step? This ...
有效使用范围:DATA Step 。参考:Statements: RETAIN Statement - 9.2 (sas.com) Without a RETAIN statement, SAS automatically sets variables that are assigned values by an INPUT or assignment statement to missing before each iteration of the DATA step. The RETAIN statement causes the values of all v...
set sashelp.class(keep = _numeric_); *只读入数值型变量; run; drop语句的用法和keep一样,套着用就行,另外drop=选项的效率也高于drop语句。 retain语句《不可执行的语句》retains values from the previous iteration of the DATA step 这个比较重要了,我先解释下sas的运行机制 sas的data步和run语句之间其实...
retain语句《不可执行的语句》retains values from the previous iteration of the DATA step 这个比较重要了,我先解释下sas的运行机制 sas的data步和run语句之间其实是一个循环,比如当使用set语句的时候,每次set一条观测,一直运行到run;再返回程序开头,继续set第二条观测值,一直将数据集的观测值读取完。
In this paper I will focus on the RETAINstatement, but with an eye toward certain general properties of the SAS DATA step. Looking at the DATA step from the perspective of a particular statement allows for an immediate, and concrete, grasp of what otherwise might feel like a rather abstract...
a DATA step can contain multiple SET statements. 2. RETAIN的作用:对于数据集中新声明的变量,SAS会在data步循环执行开始时将其置为空值,而如果该变量是retain的变量,则不被置空。 The RETAIN statement prevents SAS from re-initializing the values of new variables at the top of the DATA step.Previous...
SAS places the variables in the dataset in the order that they are referenced in the data step. Some people of adopted using the RETAIN statement, whose purpose if to RETAIN variable, as an easy way to set the order of the variables by using it as the first place the variables are ...
For this purpose, we will use a DATA Step with a RETAIN statement. Data test6; Set test5; Retain Var3; If Var3_old = . Then Var3 = 10; Run; The resulting output dataset will be as follows Var1 Var2 Var3 1510 2710 3625 4930 We can see that the value of Var3 in the second...
Next, the SAS data is set up along with each step; after that, it will complete the data step iteration. The SAS outputs of the values assigned to the variables in the programming data vectors of the SAS data set, which is already created on the Output statement, allowed control of the...