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| Test expressions | |||||
| Prerequisite Concepts | |||||
A test expression is any expression that evaluates to either true or false. Comparisons are all test expressions. Test expressions can only be used in conditions or saved in switch items. They have no numeric or string representations.
The simplest forms of a test expression are:
Comparisons are examples of test expressions. They take either numeric, string, or test expressions as operands and produce a test value (true or false) as a result.
Test expressions can be combined with the logical operators & (and) and | (or). Test expressions can be negated with the operator ! (not).
| Prerequisite Concepts Conditional constructs | 
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