-
Recent Books:
![[Essential Algorithms, Second Edition]](http://www.csharphelper.com/essential_algs_2e_158_200.jpg)
![[WPF 3d, Three-Dimensional Graphics with WPF and C#]](http://www.csharphelper.com/wpf3d_160_200.png)
![[The C# Helper Top 100]](http://www.csharphelper.com/top100_161_200.png)
![[Interview Puzzles Dissected]](http://www.csharphelper.com/interview_puzzles_161_200.jpg)
-
Recent Posts
-
Recent Comments
- Draw text with colors reversed along a diagonal line in C# - C# HelperC# Helper on Draw text with colors reversed in its upper and lower halves in C#
- RodStephens on Post questions, tips, tricks, and suggestions here
- Anthony on Post questions, tips, tricks, and suggestions here
- RodStephens on Find a polynomial least squares fit for a set of points in C#
- Louis Mezei on Find a polynomial least squares fit for a set of points in C#
Archives
- July 2019
- June 2019
- May 2019
- April 2019
- March 2019
- February 2019
- January 2019
- December 2018
- November 2018
- October 2018
- September 2018
- August 2018
- July 2018
- June 2018
- May 2018
- April 2018
- March 2018
- February 2018
- January 2018
- December 2017
- November 2017
- October 2017
- September 2017
- August 2017
- July 2017
- June 2017
- May 2017
- April 2017
- March 2017
- February 2017
- January 2017
- December 2016
- November 2016
- October 2016
- September 2016
- August 2016
- July 2016
- June 2016
- May 2016
- April 2016
- March 2016
- February 2016
- January 2016
- December 2015
- November 2015
- October 2015
- September 2015
- August 2015
- July 2015
- June 2015
- May 2015
- April 2015
- March 2015
- February 2015
- January 2015
- December 2014
- November 2014
- October 2014
- September 2014
- August 2014
- July 2014
- June 2014
- May 2014
- February 2014
- January 2014
- December 2013
- October 2013
- August 2013
- June 2013
- December 2012
- September 2012
- July 2012
- June 2012
- November 2011
- May 2011
- April 2011
- February 2011
- December 2010
Categories
- .NET
- 3D
- 3D graphics
- ADO.NET
- algorithms
- animation
- API
- arrays
- attributes
- audio
- books
- C#
- C# programming
- calculations
- challenges
- classes
- clipboard
- coding
- combinatorics
- console
- controls
- cryptography
- curve fitting
- database
- debugging
- dialogs
- directories
- Drag and Drop
- drawing
- drawings
- enums
- Event
- events
- example program
- Excel
- extension methods
- extensions
- files
- finance
- fonts
- formatting
- forms
- fractals
- ftp
- games
- GDI+
- generic
- geometry
- globalization
- graphics
- html
- IDE
- image processing
- inheritance
- interfaces
- internationalization
- internet
- interoperability
- LINQ
- lists
- localization
- mathematics
- memory
- menus
- MessageBox
- methods
- miscellany
- multimedia
- network
- Office
- OOP
- operators
- parsing
- performance
- phone
- PowerPoint
- printers
- printing
- productivity
- programs
- puzzles
- recursion
- reflection
- registry
- regular expressions
- serialization
- settings
- SQL
- stories
- strings
- syntax
- system
- threading
- three-dimensional graphics
- tips
- tools
- transformations
- Uncategorized
- user interface
- variables
- VBA
- web
- Windows Forms programming
- WMI
- Word
- wpf
- XAML
- XML
Meta
Category Archives: regular expressions
Use string extension methods to validate Social Security numbers in C#
This example defines three extension methods that return true if strings contain Social Security numbers. Recall that you must add extension methods to a static class and that the methods must be static. This example begins by defining a Matches … Continue reading
Move a window with a title that matches a pattern in C#
The example Set another application’s size and position in C# uses the FindWindow API function to find a window with a given title. Unfortunately FindWindow only finds the window if the title is an exact match. If you only know … Continue reading
Remove non-digits or non-letters from a string in C#
Sometimes you might want to extract only the digits, letters, or some other group of characters from a string. You could loop through the string examining each character individually. Fortunately there’s a much easier way to do this. The regular … Continue reading
List unique words in a text file in C#
This example uses regular expressions and LINQ to list the unique words contained in a text file in C#. When you enter the name of a file and click List Words, the following code executes. // List the words in … Continue reading
Posted in files, LINQ, regular expressions
Tagged C#, C# programming, count words, example, example program, files, find words, LINQ, regular expressions, unique words, Windows Forms programming
1 Comment
Understand C# regular expression symbols
The following table shows useful regular expression symbols, commands, and other items that you can use in regular expressions in C# programs. Item Purpose \ Either begins a special symbol such as \n or escapes the following character ^ Matches … Continue reading
Replace text in the lines of a string in C#
This example uses the following code to replace text in the lines of a string. private void btnGo_Click(object sender, EventArgs e) { try { Regex reg_exp = new Regex(txtPattern.Text); lblResult.Text = reg_exp.Replace( txtInput.Text, txtReplacementPattern.Text); } catch (Exception ex) { MessageBox.Show(ex.Message); … Continue reading
Posted in regular expressions, strings
Tagged C#, C# programming, example, example program, parse, parsing, patterns, regular expressions, replace, replace lines, string parsing, strings, Windows Forms programming
6 Comments
Replace text matching a pattern in C#
This example uses the following code to replace text matching a pattern within a string. // Make the replacements. private void btnGo_Click(object sender, EventArgs e) { Regex reg_exp = new Regex(txtPattern.Text); lblResult.Text = reg_exp.Replace( txtTestString.Text, txtReplacementPattern.Text); } This code creates … Continue reading
Show regular expression matches in C#
When you click the Go button, the program uses the following code to display regular expression matches in a string. Regex reg_exp = new Regex(txtPattern.Text); MatchCollection matches = reg_exp.Matches(txtTestString.Text); rchResults.Text = txtTestString.Text; foreach (Match a_match in matches) { rchResults.Select(a_match.Index, a_match.Length); … Continue reading
Use regular expressions to rename files within a date range and that match a pattern in C#
This example extends the example Use regular expressions to rename files that match a pattern in C# to let you rename files within a date range. See the previous example for most of the details. This post describes the changes … Continue reading
Use regular expressions to rename files that match a pattern in C#
This example shows how to use regular expressions to rename files. To use the program, enter a directory name and a file pattern. Also enter regular expression find and replace patterns. When you click Preview Changes, the program searches the … Continue reading
Posted in files, regular expressions
Tagged C#, C# programming, example, example program, files, pattern matching, patterns, Regex, regular expressions, rename files, Windows Forms programming
4 Comments