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Extracting "tokens" from a string

Posted on 2012-03-13
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Last Modified: 2012-03-13
Hey guys,

I'm a little stumped on the best way to approach this. Let's say I have a string like this:

{hello|hi|hey|what's up} it's {great|awesome|wonderful} to hear from you! When you get a {chance|minute|second} please read my {article|review}. Thanks!

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What I'd like to do is take this string as input and output a string with a random selection of each token. So for example:

hey it's wonderful to hear from you! When you get a second please read my review. Thanks!

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I hope this makes sense. How would you guys approach this?
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Question by:mcainc
4 Comments
 
LVL 1

Expert Comment

by:Turkey1974
ID: 37715570
Here's an example I found for C:
#include <stdio.h>
#include <stdlib.h>
int main() {
     const char *messages[] = {
         "Hello!",
         "How are you?",
         "Good stuff!"
     };
     const size_t messages_count = sizeof(messages) / sizeof(messages[0]);
     char input[64];
     while (1) {
         scanf("%63s", input);
         printf("%s\n", messages[rand() % messages_count]);
     }
     return 0;
 }



********************************************************************
Here's a batch example that randomizes the token # 1-9, hence the need for 9 greetings:

create a text file called subA.txt and add 9 comma delimited greetings to the first line:
Hello,Hi,Hey,What's up,Howdy,Hello,Hi,Hey,What's up

In a batch file use:

@echo off
for /f "tokens=%random:~-1% delims=," %%i IN (suba.txt) do @echo %%i it's wonderful to hear from you!
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LVL 86

Accepted Solution

by:
Mike Tomlinson earned 500 total points
ID: 37715895
I'm sure it could be done more elegantly with Regular Expressions but I suck at those.

Instead, here's an old school low level approach:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private Sentence sentence;

        private void Form1_Load(object sender, EventArgs e)
        {
            string template = "{hello|hi|hey|what's up} it's {great|awesome|wonderful} to hear from you! When you get a {chance|minute|second} please read my {article|review}. Thanks!";
            sentence = new Sentence(template);
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (this.sentence != null)
            {
                this.label1.Text = this.sentence.template;
                this.label2.Text = this.sentence.RandomSentence();
            }
        }


    }

    public class Sentence
    {

        private Random R = new Random();
        private List<string[]> tokens = new List<string[]>();
        private string _tokenizedSentence = "";
       
        private string _template;
        public string template
        {
            get { return _template; }
        }

        public Sentence(string template)
        {
            this.SetTemplate(template);
        }

        public void SetTemplate(string template)
        {
            this._template = template;

            bool InToken = false;
            string curChar;
            string curToken = "";
            string tokenizedSentence = "";
            for (int i = 0; i < template.Length; i++)
            {
                curChar = template.Substring(i, 1);
                switch (curChar)
                {
                    case "{":
                        if (!InToken)
                        {
                            InToken = true;
                            curToken = "";
                            tokenizedSentence = tokenizedSentence + "|";
                        }
                        else
                        {
                            // malformed template!
                        }
                        break;

                    case "}":
                        if (InToken)
                        {
                            InToken = false;
                            tokens.Add(curToken.Split("|".ToCharArray()));
                        }
                        else
                        {
                            // malformed template!
                        }
                        break;

                    default:
                        if (InToken)
                        {
                            curToken = curToken + curChar;
                        }
                        else
                        {
                            tokenizedSentence = tokenizedSentence + curChar;
                        }
                        break;
                }
            }
            if (!InToken)
            {
                this._tokenizedSentence = tokenizedSentence;
            }
            else
            {
                // malformed template!
            }
        }

        public string RandomSentence()
        {
            string output = "";
            string curChar = "";
            int tokenCounter = 0;
            for (int i = 0; i < this._tokenizedSentence.Length; i++)
            {
                curChar = this._tokenizedSentence.Substring(i, 1);
                switch (curChar)
                {
                    case "|":
                        if (tokenCounter < this.tokens.Count)
                        {
                            string[] curTokens = this.tokens[tokenCounter];
                            output = output + curTokens[this.R.Next(curTokens.Length)];
                            tokenCounter++;
                        }
                        else
                        {
                            // malformed template!
                        }
                        break;

                    default:
                        output = output + curChar;
                        break;
                }
            }
            return output;
        }

    }
}

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Author Closing Comment

by:mcainc
ID: 37716888
This is perfect!
0
 
LVL 40
ID: 37716891
I had fun with that one, thanks.

Here is the result:

Dim salutation() As String = {"hello", "hi", "hey", "what's up"}
Dim superlative() As String = {"great", "awesome", "wonderful"}
Dim timing() As String = {"chance", "minute", "second"}
Dim source() As String = {"article", "review"}
Dim rnd As New Random(CInt(Date.Now.Millisecond))

MessageBox.Show(String.Format("{0} it's {1} to hear from you! When you get a {2} please read my {3}. Thanks!", 
      salutation(rnd.Next(4)), 
      superlative(rnd.Next(3)), 
      timing(rnd.Next(3)), 
      source(rnd.Next(2))))

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Sorry for the VB, I am coaching one of my clients at his place today, and he does not have C# installed and he is coming back so I have to leave. Should be easy to convert. The Dim instructions are declarations for auto-initializing arrays. You will have to change () for [] when using the arrays. The
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