How to Use Advanced Boolean Search Symbolsby Contributing Writer
George Boole was an English mathematician who defined an algebraic system of logic that allowed logical statements to be written exactly. The symbols he implemented are known as Boolean operators and can be used to search for specific subjects on the Internet through different search engines. Boolean logic is considered the basis for digital computer logic used in programming today.
Learn the basic operators. Boolean operators are \"AND,\" \"OR,\" \"+,\" \"NOT\" and \"-.\" The words must be spelled in all capital letters to function as Boolean operators. \"AND\" guides a search for words or phrases before and after the operator that occur together. \"OR\" directs searches for either term or phase before or after the operator. The \"+\" operator finds documents with the word immediately following and may include other terms included after the first term. \"NOT\" excludes the following term from searches. The \"-\" operator removes documents from the search that include the term following the \"-\" sign.
Make complex phrases. Fundamental Boolean operators can be strung together in phrases for more complex searches. Phrases are made of terms and operators. Terms are single search words and phrases are groups of words surrounded by quotation marks. Parentheses limit the operator to the terms inside the parentheses.
Search for terms or phrases with unknown characters. The asterisk symbol () is used to specify unknown alphanumeric characters. For instance, the search \"mn\" would find \"man\" \"moon\" \"midshipman\" and so on. Searches with the asterisk as the first character are not allowed.
Search for terms similar to a known term. Fuzzy searches are used to find words with similar spellings. Add the tilde (~) after the search word to find similar words. For instance, \"~found\" will turn up documents containing \"round\" \"sound\" \"founder\" and so on.
Search for terms or phrases within a certain number of words of each other. The tilde (~) is also used for Boolean proximity searches. Add the tilde and a number to find similar words in a phrase within that number of words apart within a document. For instance, searching for \"fastest horse\"~5 will find documents that contain \"fastest\" and \"horse\" within five words of each other.
Exclude symbols in your search that are identical to Boolean operators. If your search term or phrase actually contains Boolean operators that you don't want interpreted as operators but as particular parts of the search term, use a backslash symbol (\) before the character. For instance, \"(1+1)\" should be written as \"\(1\+1\)\" to return documents containing the alphanumeric \"(1+1)\" term.
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