Sentence parsing

Question

Hi everyone I have a problem with parsing a text file into my program. The input is in a text file with sentences. Each sentence can either be on a separate line or it can be Following the previous sentece on the same line. What I need to do is to read the whole file and then cut it up into single sentences that I can put in String[] array. For example a file can be like this: This is a sentence. This is another sentence. This is a third sentence. Fourth sentence. However the trick is that I want my program to read sentences that have periods inside them that do not terminate that sentence for example: This sentence will end at 3 p.m. on February 20th. I was looking into regular expressions and just string.indexof() methods but I cannot get far with them. Thank you for all your help.

Scott Lysle · Answer

This seems to work pretty well. private ArrayList SplitSentences( string sSourceText) { string sTemp = sSourceText; ArrayList al = new ArrayList (); string [] splitSentences = Regex .Split(sTemp @(? ); for ( int i = 0; i { string sSingleSentence = splitSentences[i].Replace( Environment .NewLine string .Empty); al.Add(sSingleSentence.Trim()); } return al; } Example use: private void button5_Click( object sender EventArgs e) { ArrayList al = SplitSentences(txtParagraphs.Text); for ( int i = 0; i //populate a list box lstSentences.Items.Add(al[i].ToString()); }

Alan · Answer

It's difficult to come up with a competely water-tight solution to this but try this approach (.Net 2.0 or later) which assumes that all sentences will begin with a capital letter and that all sentences except the first will be preceded by a dot and a space: using System; using System.IO; using System.Text.RegularExpressions; using System.Collections.Generic; class Program { static void Main() { Regex r = new Regex(@\. [A-Z]); string text = File.ReadAllText(direhack.txt); // replace newline characters with a single space and remove any final spaces text = text.Replace(
  ).TrimEnd(); // find all occurrences of .  followed by a capital letter MatchCollection mc = r.Matches(text); List temp = new List (); string sentence = null; int startIndex = 0; // index of start of next sentence foreach(Match m in mc) { if (m.Index > 1) { // parse out the preceding sentence sentence = text.Substring(startIndex m.Index - startIndex + 1); temp.Add(sentence); startIndex = m.Index + 2; // update startIndex } } // add last sentence in text sentence = text.Substring(startIndex); temp.Add(sentence); string[] sentences = temp.ToArray(); // convert to array // check it worked foreach (string s in sentences) { Console.WriteLine(s); } Console.ReadKey(); } }