30 Common String Operations in C# and VB.NET

30 Common String Operations in C# and VB.NET – Part II

All the samples are based on two pre-declared string variables: strOriginal and strModified.

C#

string strOriginal = "These functions will come handy";

string strModified = String.Empty;

VB.NET

Dim strOriginal As String = "These functions will come handy"

Dim strModified As String = String.Empty

16. Count Words and Characters In a String – You can use Regular Expression to do so as shown below:

C#

// Count words

System.Text.RegularExpressions.MatchCollection wordColl = System.Text.RegularExpressions.Regex.Matches(strOriginal, @"[\S]+");

MessageBox.Show(wordColl.Count.ToString());

// Count characters. White space is treated as a character

System.Text.RegularExpressions.MatchCollection charColl = System.Text.RegularExpressions.Regex.Matches(strOriginal, @".");

MessageBox.Show(charColl.Count.ToString());

VB.NET

' Count words

Dim wordColl As System.Text.RegularExpressions.MatchCollection = System.Text.RegularExpressions.Regex.Matches(strOriginal, "[\S]+")

MessageBox.Show(wordColl.Count.ToString())

' Count characters. White space is treated as a character

Dim charColl As System.Text.RegularExpressions.MatchCollection = System.Text.RegularExpressions.Regex.Matches(strOriginal, ".")

MessageBox.Show(charColl.Count.ToString())

17. Remove characters in a String - The String.Remove() deletes a specified number of characters beginning at a given location within a string

C#

// Removes everything beginning at index 25

strModified = strOriginal.Remove(25);

MessageBox.Show(strModified);

or

// Removes specified number of characters(five) starting at index 20

strModified = strOriginal.Remove(20,5);

MessageBox.Show(strModified);

VB.NET

' Removes everything beginning at index 25

strModified = strOriginal.Remove(25)

MessageBox.Show(strModified)

Or

' Removes specified number of characters(five) starting at index 20

strModified = strOriginal.Remove(20,5)

MessageBox.Show(strModified)

18. Create Date and Time from String – Use the DateTime.Parse() to convert a string representing datetime to its DateTime equivalent. The DateTime.Parse() provides flexibility in terms of adapting strings in various formats.

C#

strOriginal = "8/20/2008";

DateTime dt = DateTime.Parse(strOriginal);

VB.NET

strOriginal = "8/20/2008"

Dim dt As DateTime = DateTime.Parse(strOriginal)

19. Convert String to Base64 - You will have to use the methods in System.Text.Encoding to convert string to Base64. The conversion involves two processes:

a. Convert string to a byte array

b. Use the Convert.ToBase64String() method to convert the byte array to a Base64 string

C#

byte[] byt = System.Text.Encoding.UTF8.GetBytes(strOriginal);

// convert the byte array to a Base64 string

strModified = Convert.ToBase64String(byt);

VB.NET

Dim byt As Byte() = System.Text.Encoding.UTF8.GetBytes(strOriginal)

' convert the byte array to a Base64 string

strModified = Convert.ToBase64String(byt)

20. Convert Base64 string to Original String - In the previous example, we converted a string ‘strOriginal’ to Base64 string ‘strModified’. In order to convert a Base64 string back to the original string, use FromBase64String(). The conversion involves two processes:

a. The FromBase64String() converts the string to a byte array

b. Use the relevant Encoding method to convert the byte array to a string, in our case UTF8.GetString();

C#

byte[] b = Convert.FromBase64String(strModified);

strOriginal = System.Text.Encoding.UTF8.GetString(b);

VB.NET

Dim b As Byte() = Convert.FromBase64String(strModified)

strOriginal = System.Text.Encoding.UTF8.GetString(b)

21. How to Copy a String – A simple way to copy a string to another is to use the String.Copy(). It works similar to assigning a string to another using the ‘=’ operator.

C#

strModified = String.Copy(strOriginal);

VB.NET

strModified = String.Copy(strOriginal)

22. Trimming a String – The String.Trim() provides two overloads to remove leading and trailing spaces as well as to remove any unwanted character. Here’s a sample demonstrating the two overloads. Apart from trimming the string, it also removes the "#" character.

C#

strOriginal = " Some new string we test ##";

strModified = strOriginal.Trim().Trim(char.Parse("#"));

VB.NET

strOriginal = " Some new string we test ##"

strModified = strOriginal.Trim().Trim(Char.Parse("#"))

23. Padding a String – The String.PadLeft() or PadRight() pads the string with a character for a given length. The following sample pads the string on the left with 3 *(stars). If nothing is specified, it adds spaces.

C#

strModified = strOriginal.PadLeft(34,'*');

VB.NET

strModified = strOriginal.PadLeft(34,"*"c)

24. Create a Delimited String – To create a delimited string out of a string array, use the String.Join()

C#

string[] strArr = new string[3] { "str1", "str2", "str3"};

string strModified = string.Join(";", strArr);

VB.NET

Dim strArr As String() = New String(2) { "str1", "str2", "str3"}

Dim strModified As String = String.Join(";", strArr)

25. Convert String To Integer - In order to convert string to integer, use the Int32.Parse(). The Parse method converts the string representation of a number to its 32-bit signed integer equivalent. If the string contains non-numeric values, it throws an error.

Similarly, you can also convert string to other types using Boolean.Parse(), Double.Parse(), char.Parse() and so on.

C#

strOriginal = "12345";

int temp = Int32.Parse(strOriginal);

VB.NET

strOriginal = "12345"

Dim temp As Integer = Int32.Parse(strOriginal)

26. Search a String – You can use IndexOf, LastIndexOf, StartsWith, and EndsWith to search a string.

27. Concatenate multiple Strings – To concatenate string variables, you can use the ‘+’ or ‘+=’ operators. You can also use the String.Concat() or String.Format().

C#

strModified = strOriginal + "12345";

strModified = String.Concat(strOriginal, "abcd");

strModified = String.Format("{0}{1}", strOriginal, "xyz");

VB.NET

strModified = strOriginal & "12345"

strModified = String.Concat(strOriginal, "abcd")

strModified = String.Format("{0}{1}", strOriginal, "xyz")

However, when performance is important, you should always use the StringBuilder class to concatenate strings.

28. Format a String – The String.Format() enables the string’s content to be determined dynamically at runtime. It accepts placeholders in braces {} whose content is replaced dynamically at runtime as shown below:

C#

strModified = String.Format("{0} - is the original string",strOriginal);

VB.NET

strModified = String.Format("{0} - is the original string",strOriginal)

The String.Format() contains 5 overloads which can be studied over here

29. Determine If String Contains Numeric value – To determine if a String contains numeric value, use the Int32.TryParse() method. If the operation is successful, true is returned, else the operation returns a false.

C#

int i = 0;

strOriginal = "234abc";

bool b = Int32.TryParse(strOriginal, out i);

VB.NET

Dim i As Integer = 0

strOriginal = "234abc"

Dim b As Boolean = Int32.TryParse(strOriginal, i)

Note: TryParse also returns false if the numeric value is too large for the type that’s receiving the result.

30. Determine if a String instance starts with a specific string – Use the StartsWith() to determine whether the beginning of a string matches some specified string. The method contains 3 overloads which also contains options to ignore case while checking the string.

C#

if (strOriginal.StartsWith("THese",StringComparison.CurrentCultureIgnoreCase))

MessageBox.Show("true");

VB.NET

If strOriginal.StartsWith("THese",StringComparison.CurrentCultureIgnoreCase) Then

MessageBox.Show("true")

End If

So those were some 30 common string operations that we saw in these two articles. Since these articles contained only a short introduction of each method, I would suggest you to explore each method in detail using the MSDN documentation. Mastering string operations can save us a lot of time in projects and improve application performance too. I hope this article was useful and I thank you for viewing it.