Substringing allows you to specify a subset of characters in a substitution text. This function is particularly useful when specifying a symbol in a field that accepts only a small number of characters.
The syntax for substringing symbols is:
-or-
- start
- The character position where the substring is to start. The first character in the original system symbol is position 1, the second is position 2, and so on. If start is positive, the system will count from the starting position to the end of the string. If start is negative (in other words, a minus sign appears before it), the system will count backwards from the ending position of the string.
- number
- The number of characters, from the starting position to the ending position of the string, that the substring is to contain. If number is not specified, the substring length will default to 1. Do not specify a negative number for number.
For example, assume that you want to specify &SYSNAME as the second-level qualifier in a data set name, and you want to limit the qualifier to two characters. If the system defined a four-character value to &SYSNAME, such as SYS1, you can specify the third and fourth characters of SYS1 using the following notation:
HILEVELQ.&SYSNAME(3:2)..LOWLVLQ
In this case, the system substitutes the third and fourth characters of SYS1 (which are S1) as the second-level qualifier, yielding:
HILEVELQ.S1.LOWLVLQ