SAS：输入输出格式 $VARYINGw. Informat-经管之家官网！

用途：
用于读入长度不一的字符记录

Details

Use $VARYINGw. when the length of a character value differs from record to record. After reading a data value with $VARYINGw., the pointer's position is set to the first column after the value.
案例：
Example 1: Obtaining a Current Record Length Directly

1. input fwidth 1. name $varying9. fwidth;

复制代码

Data Line	Results
----+----1
5shark	shark
3sunfish	sun
8bluefish	bluefish
* Notice the result of reading the second data line.

Example 2: Obtaining a Record Length Indirectly Use the LENGTH= option in the INFILE statement to obtain a record length indirectly. The input data lines and results follow the explanation of the SAS statements.

1. data one;
   
2. infile file-specification length=reclen; input @;
   
3. fwidth=reclen-9;
   
4. input name $ 1-9 @10 class $varying20. fwidth;
   
5. run;

复制代码The LENGTH= option in the INFILE statement assigns the internally stored record length to RECLEN when the first INPUT statement executes. The trailing @ holds the record for another INPUT statement. Next, the assignment statement calculates the value of the varying-length field by subtracting the fixed-length portion of the record from the total record length. The variable FWIDTH contains the length of the last field and becomes the length-variable argument to the $VARYING20. informat.

Data Line	Results
----+----1----+----2
PATEL CHEMISTRY	PATEL CHEMISTRY
JOHNSONGEOLOGY	JOHNSONGEOLOGY
WILCOX ART	WILCOX ART

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用法：

$VARYINGw. length-variable

Syntax Description
w 指定字符变量的最大宽度
specifies the maximum width of a character field for all the records in an input file.

Default:	8 if the length of the variable is undefined; otherwise, the length of the variable
Range:	1-32767

length-variable指定一个数值变量作为前面要读入的字符变量的宽度
specifies a numeric variable that contains the width of the character field in the current record. SAS obtains the value of length-variable by reading it directly from a field that is described in an INPUT statement or by calculating its value in the DATA step.

Requirement:	You must specify length-variable immediately after $VARYINGw. in an INPUT statement.
Restriction:	Length-variable cannot be an array reference.
Tip:	If the value of length-variable is 0, negative, or missing, SAS reads no data from the corresponding record. A value of 0 for length-variable enables you to read zero-length records and fields. If length-variable is greater than 0 but less than w, SAS reads the number of columns that are specified by length-variable. Then SAS pads the value with trailing blanks up to the maximum width that is assigned to the variable. If length-variable is greater than or equal to w, SAS reads w columns.

详细参考出处：
http://support.sas.com/documentation/cdl/en/lrdict/63026/HTML/default/viewer.htm#a000193602.htm