A   F e w   U s e f u l   S t r i n g   C l a s s   M e t h o d s

By Michael McIntyre

mikemc@getdotnetcode.com

All strings are derived from the .Net Framework String Class which provides many string manipulation methods.  To see all the String Class methods search .Net help using this search string: String Members

Here are some examples of the more useful methods of the String Class in action.

IndexOf(string) - Reports the index of the first occurrence of a string within a string.

Dim string1 As String = "abcd"

' Report the index of 'b' in string1

Console.WriteLine(string1.IndexOf("b"))

RESULT: 1

NOTE: Result is 1 because arrays are 0 based. In the string ‘a’ is at index 0, ‘b’ at index 1 and so forth.

Insert(index, string) - Inserts a string at a specified index position in another string.

Dim string1 As String = "abcd"

Console.WriteLine(string1)

RESULT: abcd

' Insert a dash into string1 at the index of 'b'

' Assign the result to string1

string1 = string1.Insert(string1.IndexOf("b"), "-")

Console.WriteLine(string1)

RESULT: a-bcd

Replace(string, string) - Replaces all occurrences of a specified string within a string, with another string.

Dim string1 As String = "The contest winner is NameGoesHere. Congratulations NameGoesHere!"

Console.WriteLine(string1)

RESULT: The contest winner is NameGoesHere. Congratulations NameGoesHere!

' Replace all occurances of 'NameGoesHere' in string1

' with 'Mr. Jones'.

' Assign the result to string1

string1 = string1.Replace("NameGoesHere", "Mr. Jones")

Console.WriteLine(string1)

RESULT: The contest winner is Mr. Jones. Congratulations Mr. Jones!

Remove(startIndex, count) - Deletes a specified number of characters from a string beginning at a specified position.

Dim string1 As String = "Bread Butter Eggs"

Console.WriteLine(string1)

RESULT: Bread Butter Eggs

' Remove 7 characters starting at the index of 'Butter'

string1 = string1.Remove(string1.IndexOf("Butter"), 7)

Console.WriteLine(string1)

RESULT: Bread Eggs

Split(char) - Identifies the substrings in a string that are delimited by one or more characters, then places the substrings into a string array.

Join - Concatenates a separator string between each element of a string array, yielding a single concatenated string.

Dim string1 As String = "System.Windows.Forms.Button"

Console.WriteLine(string1)

RESULT:  System.Windows.Forms.Button

' Split string1 into a string array named stringArray1

Dim stringArray1() As String = string1.Split(".")

' Write each element of stringArray1 to a line in the console.

Dim i = 0

For i = 0 To stringArray1.GetUpperBound(0)

   Console.WriteLine(stringArray1(i))

Next

RESULT:

System

Windows

Forms

Button

' Create a new single string from stringArray1 concatenating

' a separator string between each element joined from stringArray1.

Dim newString As String = String.Join("-", stringArray1)

Console.WriteLine(newString)

RESULT:  System-Windows-Forms-Button

ToCharArray - Copies the characters in a string to a Unicode character array.

Dim string1 As String = "abcd"

Console.WriteLine(string1)

RESULT: abcd

' Split string1 into a char array named charArray1

Dim charArray1() As Char = string1.ToCharArray()

' Write each element of charArray1 to a line in the console.

Dim i = 0

For i = 0 To charArray1.GetUpperBound(0)

  Console.WriteLine(charArray1(i))

Next

RESULT:

a

b

c

d

' Create a new single string from the charArray1

Dim newString As String

For i = 0 To charArray1.GetUpperBound(0)

   ' Concatenate newString, a char from charArray1,

   ' and a space.

   newString &= charArray1(i) & " "

Next

Console.WriteLine(newString)

RESULT:  a b c d

Format  - Replaces each format specification in a specified string with the textual equivalent of a corresponding object's value.

Dim airMiles As Integer = 1145

' Create a format string which includes the format specifier

' {0:#,###}

Dim formatString As String = "Air miles balance: {0:#,###}"

Console.WriteLine(formatString)

RESULT: Air miles balance: {0:#,###}

' Use the format string to format airMiles.

' Assign the result to newString.

Dim newString As String = Format(formatString, airMiles)

Console.WriteLine(newString)

RESULT: Air miles balance: 1,145

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