Progress
Report Builder
User’s Guide
- Concatenation
Produces a character value by joining two character strings or expressions, after trimming any trailing spaces from the first expression. Whether you should use the + or the - concatenation operator depends on whether you want to preserve trailing spaces. However, it is not always immediately obvious what will be considered a ’trailing’ space: see the first Example, below.
SYNTAX
expression
An expression whose value is a character string.
EXAMPLEThis expression formats the city, state, and postal code for an address:
But if there are any trailing spaces in the City or State fields, the result may look odd:
Using the ’-’ concatenation operator will remove trailing spaces. However, incautious use of ’-’ may also give an undesired result. Substituting ’-’ for ’+’ in the example expression above would produce
with no spaces at all, because even the literal spaces would be seen as trailing spaces and removed once they’d been appended.
To solve the problem, using the ’+’ operator behind any spaces you wish to preserve:
will produce the result desired:
NOTE
If any of the string values you concatenate is UNKNOWN, then the result is the UNKNOWN value (?). This might lead to unexpected results if a field used in an expression is not mandatory. For example, you might have fields for a person’s first name, last name, and middle initial. You might combine these into a full name with an expression like the following:
If Mid-Init is not a mandatory field, then in some records Mid-Init can be set to UNKNOWN (?). If so, the result of the expression is UNKNOWN. You can avoid this by using the following expression:
which causes the middle substring to be either Mid-Init with a space appended, or empty, depending on whether Mid-Init evaluates as not-UNKNOWN.
Copyright © 2004 Progress Software Corporation www.progress.com Voice: (781) 280-4000 Fax: (781) 280-4095 |