C # Learning record 5--regular expressions Regular expression

A regular expression that uses a string to match a series of strings that conform to a certain standard. Very useful for checking the format of strings, for example, checking the format of information when registering for a login.

C # Regular expression under namespace System.Text.RegularExpressions

Example 1.

1 usingSystem;2 usingSystem.Collections.Generic;3 usingSystem.Linq;4 usingSystem.Text;5 usingSystem.Threading.Tasks;6 usingSystem.Text.RegularExpressions;7 namespaceregextest8 {9     class ProgramTen     { One         Static voidMain (string[] args) A         { -             varSTR1 ="One , three four."; -Regex reg =NewRegex (",|;| "); the             foreach(stringStrinchReg. Split (str1)) -             { -                 if(str. Length! =0) - Console.WriteLine (str); +                 } - Console.readkey (); +         } A     } at}

Line six, using the corresponding namespace
14 lines, create an instance of the regex, the contents of the parentheses indicate: a single comma or a single semicolon or a single space

15 lines in foreach, Reg. Split (str1) means that str1 is split as regular expressions by calling the split method of the Reg instance

Get results

Example 2

1 usingSystem;2 usingSystem.Collections.Generic;3 usingSystem.Linq;4 usingSystem.Text;5 usingSystem.Threading.Tasks;6 usingSystem.Text.RegularExpressions;7 namespaceregextest8 {9     class ProgramTen     { One         Static voidMain (string[] args) A         { -             varSTR1 ="text, Test tux tax."; -Regex reg =NewRegex (@"(t\s+t) (\s|,\s|;\ s|.)"); theMatchCollection coll1 =Reg. Matches (STR1); -             foreach(Match matchinchcoll1) -             { -                 if(Match. Length! =0) + Console.WriteLine (match. ToString ()); -             } + Console.WriteLine (); ARegex REG2 =NewRegex (@"(t\s+x) (\s|,\s|;\ s|.)"); atMatchCollection coll2 =REG2. Matches (STR1); -             foreach(Match matchinchcoll2) -             { -                 if(Match. Length! =0) - Console.WriteLine (match. ToString ()); -             } in Console.readkey (); -         } to     } +}

Match by using match

The meaning of the 14 line is that the match begins with T, with one or more non-null characters in the middle (\s (uppercase) denotes any non-null character, + denotes one or more), followed by T, and finally with a space (\s (lowercase)), or a comma and a space, or a semicolon and space, or dot character. The same 22 lines, just changed to the heel X

The @ symbol in front of the quotation mark refers to the contents of the quotation mark are not escaped, so you do not need to add a \ before each \s \s.

15 lines MatchCollection coll1 = Reg. Matches (STR1);

The right side of the equal sign returns a matching set of str1 that matches the regular expression and assigns a value to the Matchcoll type Coll1

Results

C # Learning record 5--regular expressions Regular expression