Count specific character occurrences in a string

Question

What is the simplest way to count the number of occurrences of a specific character in a string   That is  I need to write a function  countTheCharacters    so that  str    the little red hen  count   countTheCharacters str  e     Count should equal 4 count   countTheCharacters str  t     Count should equal 3

User · Answer

Another possibility is to use a regular expression:

string a = "this is test";
string pattern = "t";
System.Text.RegularExpressions.Regex ex = new System.Text.RegularExpressions.Regex(pattern);
System.Text.RegularExpressions.MatchCollection m = ex.Matches(a);
MessageBox.Show(m.Count.ToString());

Please convert this into VB.NET.

User · Answer

The most straightforward is to simply loop through the characters in the string   Public Function CountCharacter ByVal value As String  ByVal ch As Char  As Integer   Dim cnt As Integer   0   For Each c As Char In value     If c   ch Then        cnt    1     End If   Next   Return cnt End Function   Usage   count   CountCharacter str   e C    Another approach that is almost as effective and gives shorter code is to use LINQ extension methods   Public Function CountCharacter ByVal value As String  ByVal ch As Char  As Integer   Return value Count Function c As Char  c   ch  End Function

User · Answer

var charCount    string with periods     Count x   gt         x

User · Answer

Trying to find the amount of     in the text       if txtName looks like  hi   hi  then intdots will   3     Dim test As String   txtName Text     Dim intdots As Integer   0     For i   1 To test Length         Dim inta As Integer   0   1         Dim stra As String   test Substring inta          If stra       Then             intdots   intdots   1         End If     Next     txttest text   intdots

User · Answer

Use   Dim a inputString   InputBox  Enter String    Enter Value        MyString   UCase inputString   MsgBox MyString  Dim stringLength  stringLength   Len MyString   Dim temp  output       i   1 Do     temp   Mid MyString  i  1       MsgBox temp  amp  i      CharacterCount   len MyString  - len Replace MyString  temp            MyString   Replace MyString  temp           output   output  amp  temp  amp        amp  CharacterCount  amp  vbNewline  Loop While MyString  lt  gt      MsgBox output

User · Answer

I think this would be the easiest   Public Function CountCharacter ByVal value As String  ByVal ch As Char  As Integer   Return len value  - len replace value  ch       End Function

User · Answer

Private Sub Data KeyPress sender As Object  e As KeyPressEventArgs  Handles Data KeyPress     If Not IsNumeric e KeyChar  And Not e KeyChar   ChrW Keys Back  And Not e KeyChar       Then         e Handled   True     Else         If e KeyChar       And Data Text ToCharArray   Count Function c  c         gt  0 Then             e Handled   True         End If     End If End Sub

User · Answer

I use the following function  It is not the most memory efficient but it is very simple to understand  supports multiple compare methods  is only 4 lines  is fast  mostly works in VBA too  will find not just individual characters but any search string  I often search for VbCrLf  s     Only thing missing is the ability to start search from a different  Start       Function inStC myInput As String  Search As String  Optional myCompareMethod As Long   CompareMethod Text  As Long         If InStr 1  myInput  Search  myCompareMethod    0 Then Return 0         Return UBound Split myInput  Search   myCompareMethod       End Function   One thing I like is that it is compact to use example   str  the little red hen  count inStC str  e    count should equal 4 count inStC str  t    count should equal 3   While I am here  I would like to shill my inStB function  which  instead of returning a count of a string  it will simply return a boolean if the search string is present  I need this function often and this makes my code cleaner   Function inStB myInput As String  Search As String  Optional Start As Long   1  Optional myCompareMethod As Long   CompareMethod Text  As Boolean     If InStr Start  myInput  Search  myCompareMethod   gt  0 Then Return True     Return False End Function

User · Answer

Public Class VOWELS      Private Sub Button1 Click sender As Object  e As EventArgs  Handles Button1 Click         Dim str1  s  c As String         Dim i  l As Integer         str1   TextBox1 Text         l   Len str1          c   0         i   0         Dim intloopIndex As Integer         For intloopIndex   1 To l             s   Mid str1  intloopIndex  1              If  s    A  Or s    a  Or s    E  Or s    e  Or s    I  Or s    i  Or s    O  Or s    o  Or s    U  Or s    u   Then                 c   c   1             End If         Next         MsgBox  No of Vowels      c ToString      End Sub End Class

User · Answer

Here is the direct code that solves the OP s problem           Dim str As String    the little red hen           Dim total As Int32          Dim Target As String    e          Dim Temp As Int32         Dim Temp2 As Int32   -1 Line50          Temp   str IndexOf Target  Temp2   1          Temp2   Temp         If Temp  lt  gt  -1 Then                Means there is a target there             total   total   1             GoTo Line50         End If          MessageBox Show CStr total     Now  this is a handy function to solve the OP s problem       Public Function CountOccurrence ByVal YourStringToCountOccurrence As String  ByVal TargetSingleCharacterToCount As String  As Int32         Dim total As Int32          Dim Temp As Int32         Dim Temp2 As Int32   -1 Line50          Temp   YourStringToCountOccurrence IndexOf TargetSingleCharacterToCount  Temp2   1          Temp2   Temp         If Temp  lt  gt  -1 Then                Means there is a target there             total   total   1             GoTo Line50         Else             Return total         End If     End Function   Example of using the function   Private Sub Button1 Click sender As System Object  e As System EventArgs  Handles Button1 Click     Dim str As String    the little red hen       MessageBox Show CStr CountOccurrence str   e           It will return 4 End Sub

User · Answer

What huge codes for something so simple   In C   create an extension method and use LINQ   public static int CountOccurences this string s  char c        return s Count t   gt  t    c       Usage   int count    toto is the best  CountOccurences  t      Result  4

User · Answer

When I found this solution I was looking for something slightly different as the string I wanted to count was longer than one character  so I came up with this solution       Public Shared Function StrCounter str As String  CountStr As String  As Integer         Dim Ctr As Integer   0         Dim Ptr As Integer   1         While InStr Ptr  str  CountStr   gt  0             Ptr   InStr Ptr  str  CountStr    Len CountStr              Ctr    1         End While         Return Ctr     End Function

User · Answer

I found the best answer  P    String ToString Count - String ToString Replace  e       Count String ToString Count - String ToString Replace  t       Count

User · Answer

Thanks   guffa  The ability to do it in one line  or even within a longer statement in  NET is very handy  This VB NET example counts the number of LineFeed characters   Dim j As Integer   MyString Count Function c As Char  c   vbLf    j returns the number of LineFeeds in MyString

User · Answer

Or  in VB NET    Function InstanceCount ByVal StringToSearch As String                         ByVal StringToFind As String  As Long     If Len StringToFind  Then         InstanceCount   UBound Split StringToSearch  StringToFind       End If End Function

User · Answer

Use   Function fNbrStrInStr strin As Variant  strToCount As String      fNbrStrInStr   UBound Split strin  strToCount   - LBound Split strin  strToCount   End Function   I used strin as variant to handle very long text  The split can be zero-based or one-based for low end depending on user settings  and subtracting it ensures the correct count   I did not include a test for strcount being longer than strin to keep code concise

User · Answer

Using Regular Expressions     Public Function CountCharacter ByVal value As String  ByVal ch As Char  As Integer   Return  New System Text RegularExpressions Regex ch   Matches value  Count End Function

User · Answer

Public Function CountOccurrences ByVal StToSerach As String  ByVal StToLookFor As String  As Int32      Dim iPos   -1     Dim iFound   0     Do         iPos   StToSerach IndexOf StToLookFor  iPos   1          If iPos  lt  gt  -1 Then             iFound    1         End If lt br  gt      Loop Until iPos   -1     Return iFound End Function   Code Usage   Dim iCountTimes As Integer   CountOccurrences  Can I call you now     a     Also you can have it as an extension    lt Extension   gt    Public Function CountOccurrences ByVal StToSerach As String  ByVal StToLookFor As String  As Int32     Dim iPos   -1     Dim iFound   0     Do         iPos   StToSerach IndexOf StToLookFor  iPos   1          If iPos  lt  gt  -1 Then             iFound    1         End If     Loop Until iPos   -1     Return iFound End Function   Code Usage   Dim iCountTimes2 As Integer    Can I call you now   CountOccurrences  a

User · Answer

I suggest you to do it like this   String Replace  e       Count String Replace  t       Count   You can also use  Split  e   Count - 1 or  Split  t   Count - 1 respectively  but it gives wrong values if you  for instance have an e or a t at the beginning of the String

User · Answer

This is the simple way   text    the little red hen  count   text Split  e   Length -1   Equals 4 count   text Split  t   Length -1   Equals 3

User · Answer

You can try this   Dim occurCount As Integer   Len testStr  - Len testStr Replace testCharStr

User · Answer

eCount   str Length - Replace str   e       Length tCount   str Length - Replace str   t       Length

User · Answer

I use LINQ  and the solution is very simple   Code in C    count   yourString ToCharArray   Count c   gt  c     e      The code in a function   public static int countTheCharacters string str  char charToCount      return str ToCharArray   Count c   gt  c    charToCount       Call the function   count   countTheCharacters yourString   e

User · Answer

Another possibility is to work with Split   Dim tmp   As String tmp   Split Expression  Delimiter  Dim count As Integer   tmp Length - 1

User · Answer

Conversion of Ujjwal Manandhar s code to VB NET as follows     Dim a As String    this is test  Dim pattern As String    t  Dim ex As New System Text RegularExpressions Regex pattern  Dim m As System Text RegularExpressions MatchCollection m   ex Matches a  MsgBox m Count ToString

User · Answer

Here s a simple version     text count function x  x    a     The above would give you the number of a s in the string   If you wanted to ignore case   text count function x  Ucase x     A     Or if you just wanted to count letters   text count function x  Char IsLetter x    True    Give it a shot

[vb.net] Count specific character occurrences in a string

Examples related to vb.net

Examples related to string