It relies on implementing & and | operators used by & and ||, as stated in MSDN 7. There is no such ordering universally defined. You cannot just show the end result when your boolean expressions are being short-circuited. This topic discusses the meaning of AND, OR, AND NOT, and other operators allowed in Boolean search queries. Most programming languages should obey this convention unless they are really weird. I wasn't trying to show the order of evaluation, just the fact that the right half of the | was evaluated period when it normally wouldn't be :) In the normal set of boolean connectives (from a logic standpoint), and is higher-precedence than or, so A or B and C is really A or (B and C). Boolean algebra involves three primitive operators, one unary (takes one operand) and two binary (takes two operands)the unary operator is the logical negation (NOT) operator. To Top Boolean and Proximity Operators operator is similar to the operator in that returns a match if both words being searched for are in the same page. Useful tip: You can an ampersand (&) instead of typing in the word AND. If you add AND operator between your two keywords, the search results will show only results that include both of your keywords. Also in C#, the | operator has a higher precedence than both || and &.īy printing out the values, you can see that if I used the typical || operator, only the first True would be printed - followed by the result of the expression which would have been True also.īut because of the higher precedence of |, the true | false is evaluated first (resulting in true) and then that result is &ed with false to yield false. Boolean search operators are used to combine or exclude the keywords. In C#, | is a logical operator that performs the same boolean logic as ||, but does not short-circuit. If you include operators such as AND and OR, we will combine them in this order: NEAR. Then any operations outside the parentheses are. The following activity allows you to practice remembering the basic laws of Boolean algebra and simplifying Boolean expressions. Expressions inside brackets are always evaluated first. As always, the operations within the innermost pair is performed first, followed by the next pair out, etc., until all operations within parentheses have been completed. The order of operations for Boolean algebra, from highest to lowest priority is NOT, then AND, then OR. If you really want to freak him out try: bool result = True() | False() & False() ProQuest assumes your search terms should be combined in a certain order. From wikipedia on boolean logic: In such cases of ambiguity, parentheses may be used to clarify the order of operations.
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