Combine a Regular Expression pattern

following sample code check string 2 regular expression patterns.

using system.collections.generic; using system.io; using system.text; using system.text.regularexpressions; namespace consoleapp {    internal class program     {         private static void main()         {             string[] contents = file.readalllines("book.txt",encoding.default);            var = new list<string>();             var rx = new regex("^\\d{1,2}\\.([a-za-z0-9]{1,}|\\d{1,2}|[ ]{1,})|^[a|b]{1}\\.(\\d{1,2})");             var rx1 = new regex("\\d$");             foreach (string content in contents)                 if (rx.ismatch(content) && rx1.ismatch(content))                     a.add(string.format("[*{0}*]", content));                 else                     a.add(content);             file.writealllines("newbook.txt", a.toarray(), encoding.default);         }     } }

from above combine simple expression

  var rx = new regex("^\\d{1,2}\\.([a-za-z0-9]{1,}|\\d{1,2}|[ ]{1,})|^[a|b]{1}\\.(\\d{1,2})");   var rx1 = new regex("\\d$");

into single pattern.

that combining regular expression pattern rx , rx1 single regular expression pattern.

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arun kumar non ascii

hi murray,

var rx = new regex("^\\d{1,2}\\.([a-za-z0-9]{1,}|\\d{1,2}|[ ]{1,})|^[a|b]{1}\\.(\\d{1,2})");

where pattern rx  checks string  start number a|b.

in condition

var teststrings = new string[] { "12.thisisatest$", "12.thisisatest9", "12.1234   4", "12.1234   $", "12.c.12abcdef", "12.a.12abcdef", "12.a.12abcdef9","1. introduction","1.1 hello world","1.2 program structure","a.1 introduction","a.2 recommended tags","a.2.1 <c>","a.2.8 <param>" };

its print  on console "bad"...

but you're mere solution regular expression shuould be

 var rx = new regex("(^\\d{1,2}\\.([a-za-z0-9]{1,}|\\d{1,2}|[ ]{1,})|^[a|b]{1}\\.(\\d{1,2}))(.*?)(\\d$)");

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arun kumar non ascii

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