Boolean
Developed by the English mathematician and computer pioneer George Boole, a Boolean consists of operators such as AND, OR, NOT and XOR. Generally, Booleans are commonly used in programming and today in Internet search engines. Boolean expressions are expressions that result in the value of either TRUE or FALSE.
As mentioned above a user can use Boolean searches to help locate more exact matches in Internet searches. For example, a user could search for computers help and DOS, which would search for any document containing computer help that also contain the word DOS. Performing Boolean searches often help users find results relating more to what the user may need to find. In addition to using a Boolean operator, many search engines also substitute AND with + and NOT with -, so using our same above example a user could type computer help +dos to achieve the same results.
Below is an example chart that help explains the Boolean operations even more by giving examples and explanations of each of the different Boolean situations.
| Example data = "Computer Hope is a location where users can find free computer help and information" | Boolean | Value_1 | Value_2 | Explanation | Results | | AND | Free | Help | Because the above example data contains both "free" and "help" the results would be TRUE. | TRUE | | AND | Expensive | Help | Although the above example does have "help", it does not contain "expensive" therefore the result would be FALSE. | FALSE | | OR | Free | Help | The above example data has both "free" and "help" but the OR Boolean only requires one or the other therefore this would be TRUE. | TRUE | | OR | Expensive | Help | Although "expensive" is not in the example data, it still does contain "help" therefore this would still remain TRUE. | TRUE | | NOT | Free | | The above example does contain "free", therefore the result would be FALSE. | FALSE | | NOT | Expensive | | The above example does not contain "expensive", therefore this result would be TRUE. | TRUE | | XOR | Free | Help | The above example contains both "free" and "help", the XOR Boolean only requires one or the other but not both, therefore this is FALSE. | FALSE | | XOR | Expensive | Help | The above example does not contain "expensive" but does contain "help", therefore this would be TRUE. | TRUE | |
Also see: Conditional statement, Operator, Programming definitions, XOR
