Bit mark character string retrieval technique

Abstract

The invention relates to a string retrieval technique using a bit to correspond to a plurality of character elements and uses n bits to correspond to all character elements. All character elements are divided into n groups, and n bits of one data which are all 0 and noted as W are used for marking the character element information of string groups. If a character element P1 of string S belongs to the n group, the n bit of W is marked as 1, and similarly, W is marked according to the groups of other character elements P2, P3, P3, and the like of S to finish marking W of all character elements. Information recording S is called a bit value of S and the mode is called 1 marking. According to logic algebra principle, n bits of one data which are all 1 and noted as W can also be used for marking the character element information forming the strings. If one character element P of S belongs to the n group, the corresponding n bit of the data W is marked as 0, and the mode is called 0 marking. Whether Sb does not include, includes or may include all character elements of the retrieval key word Sb can be judged by comparing bit value Wa of Sa, Wa and bit value Wb of Sb, and Wb of Sb. For example, bit implication calculation is carried out on Wa and Wb. If all bits have implication relation, Sb includes or may include all character elements of Sa. If necessary, such result can be got by a bit-by-bit character comparison method. Bit marking can be used for normal retrieval, as well as for reverse retrieval. If bit n used for marking is over two times of the average length m of the string, combination of bits corresponding to a group of character elements can be used for marking to improve screening efficiency, and the method is called multi-bit marking. For multi-bit marking, bit-by-bit character comparing method can also be used for finally judging whether the Sb includes Sa.

Description

technical field [0001] The invention is a character string retrieval technology, and the purpose is to improve the speed of character string fuzzy retrieval. One bit (bit) corresponds to several character elements, and n bits correspond to all character elements, that is, all character elements are divided into n groups, and n bits of a data are all 0, recorded as W F , to mark the meta-information of the characters that make up the string. If a character element P of several strings S 1 Belongs to the nth group, correspondingly mark the nth bit of W as 1, similarly, according to S other character elements P 2 ,P 3 ,P 4 ...The group to which it belongs marks W, and after completing all character meta-marks, W records the information of S, which is called the "bit value" of S, and this method is called 1 mark. According to the principle of logic algebra, it is also possible to use n bits of data that are all 1, denoted as W T , to mark the meta-information of the characte...

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Problems solved by technology

[0005] On October 19, 2004, I applied for the patent of "Prime Number Substitution String Retrieval Technology", application number 200410067258.X. String retrieval technology", in order to achieve better results, more space is needed to store the prime number product value

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