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However, there can be many ways to write a regular expression for the same set of strings: for example, (Hän|Han|Haen)del also specifies the same set of three strings in this example. Most formalisms provide the following operations to construct regular expressions. Boolean "or" A vertical bar separates alternatives.
The (standard) Boolean model of information retrieval (BIR) [1] is a classical information retrieval (IR) model and, at the same time, the first and most-adopted one. [2] The BIR is based on Boolean logic and classical set theory in that both the documents to be searched and the user's query are conceived as sets of terms (a bag-of-words model ).
A law of Boolean algebra is an identity such as x ∨ (y ∨ z) = (x ∨ y) ∨ z between two Boolean terms, where a Boolean term is defined as an expression built up from variables and the constants 0 and 1 using the operations ∧, ∨, and ¬. The concept can be extended to terms involving other Boolean operations such as ⊕, →, and ≡ ...
Full-text search#Boolean queries To a section : This is a redirect from a topic that does not have its own page to a section of a page on the subject. For redirects to embedded anchors on a page, use {{ R to anchor }} instead .
strings Text to be searched for. [drive:][path]filename Specifies a file or files to search. Flags: /B Matches pattern if at the beginning of a line. /E Matches pattern if at the end of a line. /L Uses search strings literally. /R Uses search strings as regular expressions. /S Searches for matching files in the current directory and all ...
[1] [2] Indeed, a Boolean variable may be regarded (and implemented) as a numerical variable with one binary digit , or as a bit string of length one, which can store only two values. The implementation of Booleans in computers are most likely represented as a full word , rather than a bit; this is usually due to the ways computers transfer ...
In computer science, a Boolean expression is an expression used in programming languages that produces a Boolean value when evaluated. A Boolean value is either true or false.A Boolean expression may be composed of a combination of the Boolean constants True/False or Yes/No, Boolean-typed variables, Boolean-valued operators, and Boolean-valued functions.
In the theory of relational databases, a Boolean conjunctive query is a conjunctive query without distinguished predicates, i.e., a query in the form () (), where each is a relation symbol and each is a tuple of variables and constants; the number of elements in is equal to the arity of .