sas transpose过程

transpose基本语法

Note: If output-data-set does not exist, PROC TRANSPOSE creates it by using the
DATA n naming convention. ??
Note: If you omit the VAR statement, the TRANSPOSE procedure transposes all of
the numeric variables in the input data set that are not listed in another statement. ??
Note: You must list character variables in a VAR statement if you want to transpose
them. ??

被转置后数据集中的默认变量名时啥？

_NAME_:is the default name of the variable that PROC TRANSPOSE creates to identify the source of the values in each observation in the output data set

This variable is a character variable whose values are the names of the variables that are transposed from the input data set

默认标签为：NAME OF FORMER VARIABLE

col1-coln:其余的列都是默认命名

如何改变默认变量名？

The NAME= option specifies a name for the _NAME_ variable

The PREFIX= option specifies a prefix to use in constructing names for transposed variables in the output data set

proc transpose data=sasuser.ctargets
　　out=work.ctarget2
　　name=Month
　　prefix=Ctarget;
run;

改变前后效果如下

by statement对转置数据集进行分组

For each BY group, PROC TRANSPOSE creates one observation for each variable that it transposes. The BY variable itself is not transposed

我的理解：转置后的数据集第一列的值全都是以前的变量名，如果用by后，by变量并不会进行转置，而是在第一列作为分组变量出现，(考虑单个by的情况)第二列才是_NAME_列

对每一个by组都会将以前的变量列出来一遍

var statement

var中的变量是需要进行转置的变量，声明哪些就只会对哪些进行转置，其他don‘t care！