This tutorial will cover the following tasks in C#:
- How to count the characters in a string
- How to assign a file’s directory location to a variable
- How to create a list variable
- How to pull/read a CSV file column into a list variable
- How to clean strings using Regex to remove non alpha numeric characters as the strings are being read into a list
- How to remove duplicate word entries from a list
- How to order a list
- How to write variables to the console, including a list’s elements
Assumptions:
You already know how to create projects in Visual Studio.
If you do not how to do this search online using the following term “how to create C# console applications in visual studio”.
Prerequisites:
First you will need to generate a CSV file with random words using this site:
https://onlinerandomtools.com/generate-random-csv
For the option “how many columns to generate” set the value to 1.
For testing purposes create 1000 rows.
Download the csv file generated and save it using the name “words”.
Summary of how the code works:
The code works by reducing the initial list (i.e. the supplied CSV file of random words) down to only words that match the number of characters of the user word, typically referred to as “string length”.
Once that subset of words has been created the code will then compare the user word’s letters against each letter, referencing the relative position, in each word in the subset.
Note: there is still significant room for optimization but the code is functional and works well as an accessible, human readable tutorial.
Use case example:
If the user enters the word “apple” the dictionary subset will be reduced down to 5 letter words only. These five letter words are then compared to the user word, each word and letter at a time. So if the first word in the list was “cabin” the comparison would jump to the next word in the list as the “a” in “apple” does not match the “c” in “cabin”. If the next word in the dictionary was “acorn” the first letters would match but the comparison would jump to the next word when the “c” and “p” did not match.
Instructions:
Create a C# console application called CrosswordSolver in Visual Studio.
Move the CSV file called “Words” into the bin directory of the project folder, i.e. CrosswordSolver\CrosswordSolver\bin
Open the project CrosswordSolver and paste the C# code below into the default window replacing the default cs page code.
The hardcoded example of a user word is:
string userWord = “a****”;
The user can use * to represent characters unknown, for example ap*le.
Note: The CSV file you randomly generated may have no examples of 5 letter words begining with the letter “a” so experiment with other characters.
You can test the letter comparison functionality by uncommenting the two sections of code immediately following the comments “Test letter comparison”.
To test your CSV file has been read into memory you can uncomment the section of code immediately following “Test that dictionary has been read into memory”.
The C# code:
using System; using System.IO; using System.Linq; using System.Collections.Generic; using System.Text.RegularExpressions; namespace CrosswordSolver { class Program { static void Main(string[] args) { int c = 0; //User input //NOTE: Use * to represent characters unknown string userWord = "a****"; int wordLength = userWord.Length; //Assign directory location of the csv file containing the collection of words to a variable string projectFolder = Directory.GetParent(Directory.GetCurrentDirectory()).Parent.FullName; string file = Path.Combine(projectFolder, "words.csv"); //Display dictionary location in console Console.WriteLine("Dictionary location: " + file); var dictionary = new List<string>(); using (var rd = new StreamReader(file)) //Pull file column into dictionary list without cleaning //{ // while (!rd.EndOfStream) // { // var splits = rd.ReadLine().Split(','); // dictionary.Add(splits[0]); // } //} //Pull file column into dictionary list while cleaning { while (!rd.EndOfStream) { var splits = rd.ReadLine().Split(','); //string clean is done with Regex dictionary.Add(Regex.Replace(splits[0], "[^A-Za-z0-9 ]", "")); } } //Test that dictionary has been read into memory //Console.WriteLine("The dictionary contains the following words:"); //foreach (var element in dictionary) //Console.WriteLine(element); //Remove duplicate word entries //c = dictionary.Count; //Console.WriteLine("The dictionary contains " + c + " words"); dictionary = dictionary.Distinct().ToList(); //c = dictionary.Count; //Console.WriteLine("The dictionary contains " + c + " words"); // Count the elements in the List and display test parameters c = dictionary.Count; Console.WriteLine("The dictionary contains " + c + " words"); Console.WriteLine("User entered the string: " + userWord); Console.WriteLine(userWord + " has " + wordLength + " characters"); userWord = userWord.ToLower(); //Reduce the dataset size based on number of characters in string IEnumerable<string> query = dictionary.Where(word => word.Length == wordLength); var subSet = new List<string>(); foreach (var word in query) subSet.Add(word); //Order List subSet = subSet.OrderBy(x => x).ToList(); c = subSet.Count; if (c != 0) { Console.WriteLine("The dictionary contains " + c + " words that are " + wordLength + " characters in length"); //Begin character and position match check var result = new List<string>(); foreach (var word in subSet) { for (int i = 0; i <= wordLength - 1; i++) { if ((word.ToLower()[i] == userWord[i]) | (userWord[i] == '*')) { //Test letter comparison (Letters match) //Console.WriteLine( //"Letter " + i + ", which is " + "\"" + word[i] + "\"" + ", of the word " + "\"" + word + "\"" + //" matches letter " + i + ", which is " + "\"" + userWord[i] + "\"" + ", of the user input " + "\"" + userWord + "\"" //); if (i == wordLength - 1) { result.Add(word); } } else { //Test letter comparison (Letters do not match) //Console.WriteLine( //"Letter " + i + ", which is " + "\"" + word[i] + "\"" + ", of the word " + "\"" + word + "\"" + //" does not match letter " + i + ", which is " + "\"" + userWord[i] + "\"" + ", of the user input " + "\"" + userWord + "\"" //); break; } } } //Test words that do not match //foreach (var word in subSetToRemove) //Console.WriteLine(word); bool isEmpty = !result.Any(); if (isEmpty) { Console.WriteLine("No matches found"); } else { c = result.Count(); Console.WriteLine("Potential matches found: " + c); foreach (var word in result) Console.WriteLine(word); } } else { Console.WriteLine("No words of " + wordLength + " characters long found"); } Console.ReadKey(); } } }
If you found this code useful be sure to like the post and comment. ☮
If you would like to know how to create a csv file with C# see this tutorial link.
If you would like to know how to create a console application in Visual Studio that won’t open a command window when it runs see this tutorial link.
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