First, the tag tag is a process of extracting specific content from text. The following code extracts words from the sentence and outputs them to the console. Class mytokenizing {static void main (string [] args) {string mystring = "i like this food, is you?"; char [] separators = {'', ',', '?', ':', '! '}; Int startPOS = 0; int endpos = 0; do {endpos = mystring.indexofany (separators, startpos); if (endpos == - 1) endpos = mystring.length; if (endpos! = Startpos) console.writeline (MyString.Substring (STARTPOS, (endpos-startpos))); startpos = (endpos 1);} while (startpos class myprocessfile {static void Main (string [] args) {const string myName = "test.txt"; Stream readLine; TextWirter writeLine; StringBuilder sb; readLine = File.OpenRead (myName); WriteLine = Console.Out; StreamReader readLineSReader = new StreamReader (readLine, Encoding.Unicode); readLineSReader.BaseStream.Seek (0, SeekOrigin.Begin); while (readLineSReader.Peek ()> - 1) {sb = new StringBuilder (readLineSReader.ReadLine ()); // insert String operation statement such as: sb.append (", 123"); console.writeline (sb.tostring ());}}} Add a column at the end: // Displays Aaaaaaa, Bbbbbbbb, CCCCCC, XXXXX / / .. .... Sb.Append (", xxxxx"); First column can use the following code to delete: // displays bbbbbbb, ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc // ... Sb.Remove (0, sb.toString (). IndexOf (',') 1); replace separator: //aaaaaaaa bbbbbbbbbbbbbbbbbcccccsb.replace (',', ' '); add line number (Linenumber has declared a premise): SB .Insert (0, lineNumber.ToString ( "000")); lineNumber ; // displays // 000 aaaaaaaa, bbbbbbbb, cccccc // 001 dddddddd, eeeeeeee, ffffff // 002 gggggggg, hhhhhhhh, iiiiii // 003 jjjjjjjj, kkkk KKKK, LLLLL 13:16 | Comments (0) July 11, 2004 # String Operation Learning Notes String operation 1. Extract the substring StringBuilder class from the string does not support substrings, so you must use the String class to extract. String mystring = "my name is ynn."; // displays "name is ynn." console.writeline (mystring.substring (3)); // displays "Ynn" console.writeline (11,3) ); 2. Comparison string String class has four methods: Compare (), Compareto (), Compareordinal (), Equals (). The Compare () method is a static version of the Compareto () method. As long as the "=" operator, the equals () method is called, and the equals () method is equivalent to "=". CompareRinal () method compares the local language and files for both strings. Example: int result; Bool Bresult; S1 = "aaaa"; s2 = "bbb"; // COMPARE () Method // RESULT value is "0" means, less than zero means S1 3.1 Format Digital Format Character Description and Association Attributes C, C currency format. D, D decimal format. e, e scientific count (index) format. f, f fixed point format. g, g is regular format. n, n digital format. R, R round-trip format, ensures that the same value is the same as the original number when converting the digital conversion back to the number. X, x hexadecimal format. Double Val = Math.pi; console.writeLine (Val.Tostring ()); // Displays 3.14159265358979console.writeline (Val.Tostring ("e")); // Displays 3.141593e 000console.writeline (Val.Tostring "F3"); // displays 3.142int val = 65535; console.writeline (Val.Tostring ("x"))); // Displays fffconsole.writeline (Val.Tostring ("x")); // Displays fffsingle Val = 0.123f; console.writeline (Val.Tostring ("P"))); // DisplayS 12.30% console.writeline (Val.Tostring ("P1")); // DisplayS 12.3% default formatting in numbers and hundred Add a space between the semicolon. The custom method is as follows: where the NumberFormatinfo class is a member of the System.globalization namespace, so the namespace must be imported into the program. Single Val = 0.123f; Object myobj = Numberformatinfo.currentInfo.clone () as NumberFormatInfo; NumberFormatInfo myformat = myobj as NumberFormatInfo; myformat.PercentPositivePattern = 1; Console.WriteLine (val.ToString ( "p", myformat)); // displays 12.30%; Console.WriteLine (val.ToString ( "p1 ", myformat); // displays 12.3%; formatted has great flexibility. The following example demonstrates a meaningful currency structure: Double Val = 1234567.89; int [] groupsize = {2, 1, 3}; Object myobj = Numberformatinfo.currentInfo.clone (); Numberformatinfo My currency = myobj as NumberFormatInfo; mycurrency.CurrencySymbol = "#"; // symbol mycurrency.CurrencyDecimalSeparator = ":"; // decimal mycurrency.CurrencyGroupSeparator = "_"; // separator mycurrency.CurrencyGroupSizes = groupsize; // output # 1_234_5_67: 89console.writeline (Val.Tostring ("C", Mycurrency); 3.2 Formatting Date Output Depending on the cultural settings of the user's computer. Using system; using system.global; public class mainclass {public static void main (string [] args) {datetime dt = DateTime.now; string [] format = {"d", "d", "f", "f" "" G "," G "," M "," R "," S "," T "," T "," U "," U "," Y "," DDDD, MMMM DD YYYY ", "DDD, MMM D /" '/ "YY", "DDDD, MMMM DD", "M / YY", "DD-MM-YY",}; String Date; For (INT I = 0; I 11:56 | Comments (0) July 8, 2004 # StringBuilder class learning notes The non-variableity of the String class makes it more like a value type rather than a reference type. Its side effects are created a new String object every time you perform character operations. The StringBuilder class solves the problem of creating a large number of objects during repeated modification of the string. Some properties and methods of the StringBuilder class The Length attribute is not read-only. Stringbuilder SB = New StringBuilder ("i live the language"); console.writeline (sb.Length = 6; // displays "i live" console.writeline (sb.toString ()); Capacity Property Description: The number of characters allocated for instances. The default capacity is 16. If a string is supplied as a parameter to the constructor, the capacity is the value of the most close to 2. MaxCapacity property description: The maximum number of characters that can be assigned this instance. Append () method description: A string representation of the given value. Stringbuilder SB = new stringbuilder (); console.writeline (sb.capacity "/ t" sb.Length); sb.append ('a', 17) Console.writeline (sb.capacity "/ t" sb.Length ); 16 0 <== Output 32 17 EnsureCapacity (int CAPACITY) method Description: If the current capacity is less than the specified capacity, the memory allocation increases the memory space to achieve the specified capacity. Replace (Char Oldchar, Char Newchar) Method: Replace OldChar with Newchar. Replace (String OldString, String News) Method Description: Replace OldString with NewString. Replace (Char Oldchar, CHAR NEWCHAR, INT StartPOS, INT Count) Method: Replace Oldchar with Newchar between StartPos to Count-1. Replace (String OldString, String NewString, Int StartPOS, INT Count) Method Description: Replace OldString with NewString from StartPos to Count-1. TOSTRING () method Stringbuilder SB = New StringBuilder ("I live this game"); string S1 = sb.toString (); // displays "i live this game" string s2 = sb.toString (3, 4); // DisplayS "Live" here's second toString () method callstring () method for the String class () method (int StartIndex, Int length) {return m_stringvalue.substring (startIndex, length); 10:28 | Comments (0) July 7, 2004 # String class learning notes I. Common public members of the String class Static method function of Compare (String S1, STRING S2): Case size comparison. Compare (String S1, String S2, Bool Ignorecase) Static method function: IgnoreCase is True, which is not case sensitive comparison. CompareTo (String S) instance method function: Perform a case-sensitive and cultural information for a given string and an instance string. Copy (String S) Static Method Function: Returns a new string with a given string. COPYTO (int surceIndex, char [] destination, int desinterx, int count) instance method: The specified location in this instance is copied to the specified location in the Unicode characters array. Parameters: SourceIndex: Character position in this instance. Destination: A number of Unicode characters. DestinDex: Array Elements in Destination. Count: The number of characters to Destination in this instance. Routines: use system; public class copytotest {spread static void main () {string strsource = "change"; char [] destination = {'t', 'h', 'e', ',' i ',' N ',' I ',' T ',' I ',' A ',' L ',' ',' A ',' R ',' R ',' A ',' Y '}; Console.Writeline (destination); strsource.copyto (0, destination, 4, strsource.length); console.writeline (destination); strsource = "a Different String"; strsource.copyto (2, Destination, 3, 9); console.writeline (Destination);}} output: The Initial Arraythe Changed ArrayThedIffereTARRAY EndSwith (String S) function: Returns true if the instance string ends with a given string. Equals (String S) function: Returns true if the instance string has the same value as a given object. Format (iformatProvider Provider, String Format, Paramarray Args) Features: A copy of Format, where the format item has been replaced with the String equivalent of the corresponding Object instance in the ARGS. Parameter Provider: An IFORMATPROVIDER, which provides regional specific format setting information. Format: Contains zero or more format items. ARGS: An Object array containing zero or more objects to formatted. For example: string myname = "fred"; string.format ("name = {0}, Hours = {1: hh}", myname, datetime.now); fixed text is "name =" and ", Hours =", The format item is "{0}" and "{1: hh}", the value is MyName and DateTime.now. Replace (String OldString, String News "Features: Replace all of OldString with NewString in the instance string. Split (Char [] separator, int count) Parameters Separator: Separate the Unicode character array of sub-strings in this instance, and does not contain space arrays or empty references for separators. Count: The maximum number of array elements to return. For example: String delimstr = ",.:"; Char [] delimiter = delimstr.tochararray (); string word = "ONE TWO, Three: four."; String [] split = null; split = words.split (Delimiter, 4); Foreach (string s in split) {console.writeline ("- {0} -", s);} one <== Output TWothreefour. Substring (int StartPOS, INT Length) function: Returns a substring of a specified length from the specified location. TOSTRING () Features: Returns a reference to instance characters. Tostring (iformatprovider format) Features: Returns a reference to an instance string. 13:31 | Comments (0) July 6, 2004 # Regular expression learning notes (1) First, System.Text.RegularExpression Namespace 1, the Regex class can be used to create a regular expression, but also provide a number of methods. Such as: regex.replace (String Input, String Pattern, String Replacement); ------- Regexoption enumeration IGNORECase ignores case. The default case case size is RightToleft to find the input string from right to left. NONE does not set a sign. Miltiline specifies ^ and $ can match the beginning and end of the line, and the beginning and end of the string. SINGLINE specifies special characters "." Matching any character. Except for the laundry. Example: regexoptions.ignorecaseregex.ismatch (MyString, "YWSM", regexoptions.ignorecase | regexoptions.righttoleft): ------ (two main) class constructor regex (String Pattern); regex (String Pattern, Regexoption options); Example: Match YWSM: static void main (string [] args) {regex myregex = new regex ("ywsm"); system.console.writeline (MyRegex.ismatch ("The first three letters of" "Tha Alphabet are YWSM ");} Output: True If you need to set the case-sensitive case, you can use regex myregex = new regex (" ywsm ", regexoption.ignorecase; ------- ismatch () method This method can test strings See if it matches the mode of the regular expression. If you find a match, return TRUE, otherwise false. Ismatch () has a static overload method, which can use it without explicitly create a regex object. Overloads: public bool Regex.IsMatch (string input); public bool Regex.IsMatch (string input, int startat); public static bool Regex.IsMatch (string input, string pattern); public static bool Regex.IsMatch (string input , String Pattern, Regexoption Options; INPUT: Specifies a string containing the text that will retrieve. Sartat: Specifies the start character position of the search. PTTERN: Specifies the style that will match. Options: Match behavior options. Example: string inputstring = "Welcome to the ywicc, ywsmxy!"; If (Regex.IsMatch (inputstring, "ywicc", RegexOptions.IgnoreCase)) Console.WriteLine ( "Match Found"); Else Console.WriteLine ( "No Match "); ------ Replace () method instead of a matching mode with the specified string. --- Basic methods: public static string Regex.Replace (string input, string pattern, string replacement); public static string Regex.Replace (string input, string pattern, string replacement, RegexOption options); Example: with "AAA" Replace all instance code of "BBB": string infutstring = "Welcome to the aaa!"; Inputstring = regex.replace (InputString, "BBB", "AAA"); console.writeline (InputString); ---- non-static the method may alternatively specify a maximum number of starts and the subscript: Public string replace (string input, string replacement); Public string replace (string input, string replacement, int count); Public string replace (string input, string replacement, int count, int startat); Example: use after 456 123 XXX Alternatively, replace up to two, as follows: string inputstring = "123,456,123,123,123,789,333"; Regex regexp = new Regex ( "123"); inputstring = regexp.Replace (inputstring, "Xxx", 2, 4) Console.Writeline (InputString); Output: 123, 456, XXX, XXX, 123, 789, 333 ----- split () method is subjected to matching strings at each discovery. Returns a string array. using System; using System.Text; using System.Text.RegularExpressions; using System.Windows.Forms; class mysplit {static void Main (string [] args) {string inputstring = "123,456,789, ads"; string [] splitResults; splitresults = Regex.Split (inputstring, ","); StringBuilder resultsstring = new StringBuilder (32); foreach (string stringelement in splitresults) {resultsstring.Append (stringelement "/ n");} MessageBox.Show (resultsString.ToString () );}} 123 <== result 456789ads
