SAS Base (59)

Given the contents of the raw data file TYPECOLOR.DAT:

—-+—-10—+—-20—+—-30
daisyyellow

The following SAS program is submitted:

data FLOWERS;
infile ‘TYPECOLOR.DAT’ truncover;
length
Type $ 5
Color $ 11;
input
Type $
Color $;
run;

What are the values of the variables Type and Color?

A. Type=daisy, Color=yellow
B. Type=daisy, Color=w
C. Type=daisy, Color=daisyyellow
D. Type=daisy, Color=

Check Answer

Answer: D

注解：The code neither specified where to read the value of each variable nor the delimiter. SAS will start to read value from left to right, using the default delimiter, space(‘ ‘). SAS reads the first value ‘daisyyellow’ and assigns it to variable ‘Type’. As the length of ‘Type’ is 5 which means it can only hold up to 5 characters, the value is truncated to ‘daisy’. Then SAS tries to read the second value for ‘Color’, but there is nothing left in the file. SAS simply sets the value to missing.

One of the proper way to read the file would be telling SAS the position of each variable:

data FLOWERS;
infile ‘TYPECOLOR.DAT’;
length
Type $ 5
Color $ 11;
input
Type $ 1-5
Color $ 6-11;
run;

Obs	Type	Color
1	daisy	yellow

If you were not sure the length of the second variable, TRUNCOVER option would be handy. It enables you to read variable-length records when some records are shorter than the INPUT statement expects.

The following program will produce the identical result, except that the value of ‘Color’ could be any length from 0 to 15.

data FLOWERS;
infile ‘TYPECOLOR.DAT’ truncover;
length
Type $ 5
Color $ 11;
input
Type $ 1-5
Color $ 6-20;
run;