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The usual context of wildcard characters is in globbing similar names in a list of files, whereas regexes are usually employed in applications that pattern-match text strings in general. For example, the regex ^ [ \t] +| [ \t] +$ matches excess whitespace at the beginning or end of a line.
In computer science, an algorithm for matching wildcards (also known as globbing) is useful in comparing text strings that may contain wildcard syntax. [1] Common uses of these algorithms include command-line interfaces, e.g. the Bourne shell [2] or Microsoft Windows command-line [3] or text editor or file manager, as well as the interfaces for some search engines [4] and databases. [5]
In SQL, wildcard characters can be used in LIKE expressions; the percent sign % matches zero or more characters, and underscore _ a single character. Transact-SQL also supports square brackets ([and ]) to list sets and ranges of characters to match, a leading caret ^ negates the set and matches only a character not within the list.
Like a word or phrase search stemming and fuzzy searches can apply. A word input can be put in double "quotes" to turn off stemming. A phrase input can use greyspace to turn on stemming. A single word input can suffix the tilde ~ character for a fuzzy search. A single word input can suffix the star * character for a wildcard search.
Title Authors ----- ----- SQL Examples and Guide 4 The Joy of SQL 1 An Introduction to SQL 2 Pitfalls of SQL 1 Under the precondition that isbn is the only common column name of the two tables and that a column named title only exists in the Book table, one could re-write the query above in the following form:
Like a word or phrase search stemming and fuzzy searches can apply. A word input can be put in double "quotes" to turn off stemming. A phrase input can use greyspace to turn on stemming. A single word input can suffix the tilde ~ character for a fuzzy search. A single word input can suffix the star * character for a wildcard search.
Ordered search within the Google and Yahoo! search engines is possible using the asterisk (*) full-word wildcards: in Google this matches one or more words, [9] and an in Yahoo! Search this matches exactly one word. [10] (This is easily verified by searching for the following phrase in both Google and Yahoo!: "addictive * of biblioscopy".)
A simple and inefficient way to see where one string occurs inside another is to check at each index, one by one. First, we see if there is a copy of the needle starting at the first character of the haystack; if not, we look to see if there's a copy of the needle starting at the second character of the haystack, and so forth.