It is better to classify them as executable and non-executable.

All statements in a data step all be compiled, and if they pass the compiling, then they get executed. Otherwise sas supervisor issues error messages.

Non-executable statements are those providing descreptive information about the variables during the compiling stage, such as
1) length
2) label
3) format
4) informat

5) retain (it may be semi-executable)

All other statements are executable and they may also provide information about the variables during the compiling stage.

Hope this is clear.

2# bobguy
一般编程代码 都可分为 可执行语句和声明语句，像版主讲的Length retain，还有array都是申明语句，SAS是不执行的。 不知道解释的对不？

thank you for replying^^