Logical Expressions (DO IF command)

• Logical expressions can be simple logical variables or relations, or they can be complex logical tests involving variables, constants, functions, relational operators, and logical operators. Logical expressions can use any of the numeric or string functions allowed in COMPUTE transformations (see COMPUTE).
• Parentheses can be used to enclose the logical expression itself and to specify the order of operations within a logical expression. Extra blanks or parentheses can be used to make the expression easier to read.
• Blanks (not commas) are used to separate relational operators from expressions.
• A relation can include variables, constants, or more complicated arithmetic expressions. Relations cannot be abbreviated. For example, the first relation below is valid; the second is not:

Valid: (A EQ 2 OR A EQ 5) Not valid: (A EQ 2 OR 5)

• A relation cannot compare a string variable to a numeric value or variable, or vice versa. A relation cannot compare the result of a logical function (SYSMIS, MISSING, ANY, or RANGE) to a number.