SAS Base 2题？

shiyiming

73. The following SAS program is submitted:
data work.test;
First = 'Ipswich, England';
City_Country = substr(First,1,7)!!', '!!'England';
run;
Which one of the following is the length of the variable CITY_COUNTRY in the
output data set?
A. 6
B. 7
C. 17
D. 25
Answer: D

76. The following SAS program is submitted:
data work.test;
Author = 'Agatha Christie';
First = substr(scan(author,1,' ,'),1,1);
run;
Which one of the following is the length of the variable FIRST in the output
data set?
A. 1
B. 6
C. 15
D. 200
Answer: D

可以问一下解答的思路吗？

Qiong

你run一下看看，就会发现
substr(First,1,7)跟first的长度是一样的。
scan(First,1,',')的结果是默认长度200的。

shiyiming

请问substr(First,1,7)!!', '!!'England'
最后输出的字符串是什么？