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Appendix C Formula Functions Reference 469
Conditional Functions
the insert button again to add an else clause. Highlighting then or else and repetitively clicking the
insert button changes the else to expr or adds a new expr clause.
To delete a clause, select the then clause above it and press the delete key on your keyboard or click
the delete button ( ) on the formula editor keypad.
By definition, expressions that evaluate as zero are false. If an expression evaluates as missing, no clauses
are executed and missing is returned. All other numeric expressions are true.
Match
Compares an expression to a list of clauses and returns the value of the resulting expression for the first
matching clause encountered. You provide the matching expression only once and then give a match
value for each clause. When you select Match, the formula editor shows a single Match condition with
a missing expression and a missing then clause, as shown in Figure C.3.
Figure C.3 An Example of Using the Match Function
C Formula Functions Reference
After you select Match, you should highlight either expr, value, or then clause, and then enter an
expression. (Or, if you highlight an expression and click Match, the formula editor creates a new
Match conditional with the original highlighted expression as expr and nothing for the value and else
clause.) Also, keep in mind that:
• Match evaluates faster and uses less memory than an equivalent If because the variable is evaluated
only once for each row in the data table. The If condition must evaluate the variable at each If clause
for each row until a clause evaluates as true. See “Comparing Values,” p. 301, for a comparison of
Match and If conditionals.
• With If and Match, the formula editor searches down from the top of the sequence for the first true
clause and evaluates the corresponding result expression. Subsequent true clauses are ignored.
For example, consider the following two formulas for predicting a child’s height from his age. In each
case there is a base height of 58.125 inches to which a quantity is added depending on the value of the
age variable.
Note: Match ignores trailing spaces, while If does not.
Although Match returns missing for any missing values, you can also specifically match missing values.