C # Regular Expression Accumulation

Thank you: Side South Side http://www.cnblogs.com/kissknife/archive/2008/03/23/1118423.html
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------------------------------------- Regular Expression -------------------------------------------

@: String x = "d :\\ my Huang \ My doc"; string y = @ "D: \ My Huang \ My doc "; the two statements are equivalent to the classes and methods used in C #: String STR = "1"; RegEx R1 = new RegEx (@ "\ D "); -- The regular format is put in it. If it is a string of characters, it matches bool result = r1.ismatch (STR) as it is; returns trueismatch () and returns true if it is appropriate, we can only make a rough judgment on the numbers of the pure memory part \ D 0-9. (currently, we do not understand that 1.5 is not counted.) ismatch () cannot be used, because there are 1 and 5. \ D completion set \ W word character, refers to uppercase and lowercase letters, 0-9 digits, underline \ W completion set \ s blank character, including line breaks \ n, carriage returns \ r, tabs \ t, vertical tabs \ V, and page breaks \ f \ s. any character except linefeed \ n […] The format in it is used as a whole and matches a character. For example, [ABC] matches a and B matches C [^…]. Match the character splitting operations not listed in []: String Pattern = "[# $]"; // You can also write it as string pattern = "# | $ "; string input = "11 $8 $8 #99"; string [] rs = RegEx. split (input, pattern); array is 11 8 8 99 note: If you want to match. $ * ^) ([] and other strings need to be escaped, for example, "\ $", but in this case, [$] string I = "Hello, world" is not required "; regEx result = new RegEx ("Hello, world"); // trueresult. ismatch (I) is worth pondering RegEx result = new RegEx ("^ Hello, world $"); // trueregex result = new RegEx ("Hello, worl "); // falsere Gex result = new RegEx ("^ hello, worl $"); // falseregex result = new RegEx ("^ hello, worl "); // true common method string I = "hellohello"; RegEx result = new RegEx ("hello"); result. matches. count (I); // 2 pure memory part: The Count-related {n} matches the previous CHARACTER n times {n,} n times or more than N times {n, m} n to m times? Match the first character 0 or 1 + 1 or more times X 0 or the character ^ that is equal to 0 position indicates that the subsequent character must be at the beginning of the string $ the character before it must be at the end of the string. \ B matches the boundary of a word. Note: the so-called boundary is not only space, but also ,. -# $ % and so on are considered boundary for all elements in a word. (2, D, _) None of the boundary \ B matches a non-word boundary string STR = "hello, everybody, happy everyday "; regEx r = new RegEx (@ "^ hello, ([A-Z] {5}) body, happy \ 1day $"); ([A-Z] {5 }) is a group, and the \ 1 after it is referred to as R. match (STR ). groups [1]. obtain "every" string STR = "zhangranzhang"; RegEx r = new RegEx (@ "^ (? <A> [A-Z] {5}) ran \ 1 $ "); // define a name for the group console. writeline (R. matches (STR ). count); console. writeline (R. match (STR ). groups [1]. value); // use the index value console. writeline (R. match (STR ). groups ["A"]. value); // use the key value string STR = "zhangzhang ran"; RegEx r = new RegEx (@ "([A-Z] {5}) \ 1 "); console. writeline (R. replace (STR, "$1"); replace duplicate, field output Zhang ranregex r = new RegEx (@"(?: [A-Z] {5 })");?: Indicates a non-capturing group. In this case, the engine will not regroup and save it. If the group is not used, it will save resources greedy and non-Greedy. By default, the engine is greedy, but after the symbol "* +" or "other" that indicates the number of words, add? Changed to the greedy string mystr = "everyboy is good boy"; RegEx res = new RegEx (@". * Boy "); console. writeline (res. match (mystr ). value); // output everyboy is good boy non-Greedy RegEx res = new RegEx (@". *? Boy "); console. writeline (res. match (mystr ). value); // The regular expression that outputs the greedy and backtracking of everyboy is used to implement the greedy matching string mystr = "everyboy, is good boy "; regEx res = new RegEx (@". * Boy, "); in the above expression, the engine first scans the entire string. The current three-character boy match is actually moving to the end to match the last boy but is matching, when there is a problem, you can only trace back to the latest boy and then match, so the output content is everyboy, (?> ...) This is the RegEx res = new RegEx (@ "(?>. *) Boy, "); this is non-backtracking, so that the matching will fail. ismatch () returns false. Forward pre-search and reverse pre-search forward pre-search include: declare (? =), Negative statement (?!) String STR = "I love the cute nation the big world"; RegEx r = new RegEx (@ ". {3, 4} \ B (? = World) "); Replace (?! World) means that the string following the world match is not followed by the reverse pre-search positive declaration (? <=), Negative statement (? <!)