lz,你将两者在SAS上运行一下，区别不就出来了吗？比如：第一次运行 input x1 x2 @;第二次运行 input x1 x2 @@;这样一比较，二者的不同不就一目了然了吗？

One @ sign means conditional input. That is, the data record from the raw data will be saved in the input buffer and will not be saved to the corresponding variable. Only when the second "input" statement is encountered can the raw data be read into the SAS data set.

For double @@, sometimes each line of the raw data is longer than the size of SAS input variables, and the input will only stop once the end of line is encountered in the raw data set. For example,

data example
    input group $ score @@;
    datalines;
    1 100 1 200 1 300
    2 120 2 210 2 320
    3 310 3 420 3 540;
run;

proc print;
run;

In the example above you need to use double trailing @@ sign since each row of the embedded data has three observations

The output of the example looks like:

ob     group    score
1         1         100
2         1         200
3         1         300
4         2         120
5         2         210
6         2         320
7         3         310
8         3         420
9         3         540

谢谢了

多谢！！！！

可以解释下下面的@是什么作用吗？


data NYC;
input city $ 18-32 @;
if city='New York';
input FLNO 1-4 AirLine $6-18 city $ 18-32 Time $34-40;
cards;
9238 American      New York       10:00
4235 United          Philadelphia    5:00pm
798   Delta            New York       8:50
4824 North West   Houston         12:30pm
1639 South West  Chicago          4:15pm
5417 North West   New York       11:25
;
run;
Proc print data=NYC;
title 'Flight to New York City';
run;



3# liugxhk