I need to create a new CSV file. Writing my own routine wouldn't be a big task, but is there a routine in the Base Class Library for this?
Here is the function you can use to generate a row of CSV file from string list (IEnumerable(Of String) or string array can be used as well):
Function CreateCSVRow(strArray As List(Of String)) As String
Dim csvCols As New List(Of String)
Dim csvValue As String
Dim needQuotes As Boolean
For i As Integer = 0 To strArray.Count() - 1
csvValue = strArray(i)
needQuotes = (csvValue.IndexOf(",", StringComparison.InvariantCulture) >= 0 _
OrElse csvValue.IndexOf("""", StringComparison.InvariantCulture) >= 0 _
OrElse csvValue.IndexOf(vbCrLf, StringComparison.InvariantCulture) >= 0 _
OrElse csvValue.IndexOf(" ", StringComparison.InvariantCulture) = 0 _
OrElse csvValue.IndexOf(" ", StringComparison.InvariantCulture) = csvValue.Length-1)
csvValue = csvValue.Replace("""", """""")
csvCols.Add(If(needQuotes, """" & csvValue & """", csvValue))
Next
Return String.Join(",", csvCols.ToArray())
End Function
Not in the framework, the code is too simple. Trivially done with StreamWriter.Write(), you only need to do a wee bit of lifting to properly quote a string. It takes just a handful of lines:
Module CsvWriter
Public Sub WriteCsvLine(ByVal out As System.IO.TextWriter, ByVal ParamArray Values() As Object)
For ix As Integer = 0 To Values.Length - 1
If ix > 0 Then out.Write(",")
If TypeOf (Values(ix)) Is String Then
out.Write("""" + CStr(Values(ix)).Replace("""", """""") + """")
Else
out.Write(Values(ix).ToString())
End If
Next
out.WriteLine()
End Sub
End Module
Related
I am trying to convert the following VB6 code to VB.NET:
Public Function SingleToHex(ByVal Tmp As Single) As String
Dim TmpBytes(0 To 3) As Byte
Dim TmpSng As Single
Dim tmpStr As String
Dim x As Long
TmpSng = Tmp
Call CopyMemory(ByVal VarPtr(TmpBytes(0)), ByVal VarPtr(TmpSng), 4)
For x = 3 To 0 Step -1
If Len(Hex(TmpBytes(x))) = 1 Then
tmpStr = tmpStr & "0" & Hex(TmpBytes(x))
Else
tmpStr = tmpStr & Hex(TmpBytes(x))
End If
Next x
SingleToHex = tmpStr
End Function
I tried to find a function in the "Conversions" namespace, but I did not find any.
Can anybody tell me how this can easily be done?
Public Function SingleToHex(ByVal Tmp As Single) As String
Dim arr = BitConverter.GetBytes(Tmp)
Array.Reverse(arr)
Return BitConverter.ToString(arr).Replace("-", "")
End Function
First part of the code is to retrieve data from the web. It takes only a part of the second to complete the request. Second part of the code is to split data so that parts of data can be shown in different labels and it takes around 5-6 second to complete this operation?
Why is that? Can it be done faster?
First part of the code (textbox1 key down event)
If e.KeyCode = Keys.Enter Then
TextBox1.Text = UCase(TextBox1.Text)
If TextBox1.Text = "" Then
GoTo exx
Else
Dim strURL As String
Dim strSymbol As String = TextBox1.Text
strURL = " http://quote.yahoo.com/d/quotes.csv?" & _
"s=" & strSymbol & _
"&d=t" & _
"&f=snl1pmwvj1l1"
MessageBox.Show(RequestWebData(strURL))
Second part of the code and functions :
Label24.Text = (GetName2(RequestWebData(strURL), 3))
Dim myText = Label24.Text
Dim dIndex = myText.IndexOf("Inc.")
If (dIndex > -1) Then
Label24.Text = (Strings.Left(Label24.Text, dIndex + 4))
Else
Label24.Text = (Label24.Text)
End If
Dim myText2 = Label24.Text
Dim dIndex2 = myText2.IndexOf("Common")
If (dIndex2 > -1) Then
Label24.Text = (Label24.Text.Replace("Common", ""))
Else
Label24.Text = (Label24.Text)
End If
Label6.Text = (GetName(RequestWebData(strURL), 4))
Label6.Text = (GetName3(Label6.Text, 1))
Label6.Text = FormatNumber(Label6.Text, 2)
Label17.Text = (GetName(RequestWebData(strURL), 5))
Label21.Text = (GetName(RequestWebData(strURL), 7))
Dim x As String = GetName(RequestWebData(strURL), 8)
Label30.Text = GetName3(x, 1)
Label30.Text = FormatNumber(Label30.Text, 0)
Label32.Text = GetName3(x, 2)
TextBox2.Focus()
Function GetName(ByVal LineIn As String, ByVal i As Integer) As String
'Dim x As Integer
Return LineIn.Split(""",")(i)
End Function
Function GetName2(ByVal LineIn As String, ByVal i As Integer) As String
'Dim x As Integer
Return LineIn.Split("""")(i)
End Function
Function GetName3(ByVal LineIn As String, ByVal i As Integer) As String
'Dim x As Integer
Return LineIn.Split(",")(i)
End Function
Maybe it is so slow because of these three functions that I am using to split data?
I am little bit confused in this program.
I am new to Visual Basic but intermediate to C.
Actually I want to get sub-string of string without using library function of Visual Basic.
Here is the C source code I also given my VB code too.
1.The Program will get two inputs from user i.e A & B
2. Than Find the substring from B.
3. Finally Print the result.
int i,j=0,k=0,substr=0;
for(i=0;i<strlen(a);i++)
{
if(a[i]==b[j])
{
j++;
if(b[j]==0)
{
printf("second string is substring of first one");
substr=1;
break;
}
}
}
for(i=0;i<strlen(b);i++)
{
if(b[i]==a[k])
{
k++;
if(a[k]==0)
{
printf(" first string is substring of second string");
substr=1;
break ;
}
}
}
if(substr==0)
{
printf("no substring present");
}
While my code is
Dim a As String
Dim b As String
a = InputBox("Enter First String", a)
b = InputBox("Enter 2nd String", b)
Dim i As Integer
Dim j As Integer = 0
Dim k As Integer = 0
Dim substr As Integer = 0
For i = 0 To a.Length - 1
If a(i) = b(j) Then
j += 1
If b(j) = 0 Then
MsgBox("second string is substring of first one")
substr = 1
Exit For
End If
End If
Next i
For i = 0 To b.Length - 1
If b(i) = a(k) Then
k += 1
If a(k) = 0 Then
MsgBox(" first string is substring of second string")
substr = 1
Exit For
End If
End If
Next i
If substr = 0 Then
MsgBox("no substring present")
End If
End Sub
While compiling it gives following debugging errors.
Line Col
Error 1 Operator '=' is not defined for types 'Char' and 'Integer'. 17 24
Error 2 Operator '=' is not defined for types 'Char' and 'Integer'. 27 24
Part of your confusion is that .Net strings are much more than just character buffers. I'm going to assume that you can at least use strings. If you can't, use need to declare character arrays instead. That out of the way, this should get you there as a 1:1 translation:
Private Shared Function search(ByVal a As String, ByVal b As String) As Integer
Dim i As Integer = 0
Dim j As Integer = 0
Dim firstOcc As Integer
While i < a.Length
While a.Chars(i)<>b.Chars(0) AndAlso i < a.Length
i += 1
End While
If i >= a.Length Then Return -1 'search can not continue
firstOcc = i
While a.Chars(i)=b.Chars(j) AndAlso i < a.Length AndAlso j < b.Length
i += 1
j += 1
End While
If j = b.Length Then Return firstOcc
If i = a.Length Then Return -1
i = firstOcc + 1
j = 0
End While
Return 0
End Function
Shared Sub Main() As Integer
Dim a As String
Dim b As String
Dim loc As Integer
Console.Write("Enter the main string :")
a = Console.ReadLine()
Console.Write("Enter the search string :")
b = Console.ReadLine()
loc = search(a, b)
If loc = -1 Then
Console.WriteLine("Not found")
Else
Console.WriteLine("Found at location {0:D}",loc+1)
End If
Console.ReadKey(True)
End Sub
But please don't ever actually use that. All you really need is this:
Private Shared Function search(ByVal haystack as String, ByVal needle As String) As Integer
Return haystack.IndexOf(needle)
End Function
VB has a built-in function called InStr, it's part of the language. It returns an integer specifying the start position of the first occurrence of one string within another.
http://msdn.microsoft.com/en-us/library/8460tsh1(v=VS.80).aspx
Pete
Try this one, this will return a List(Of Integer) containing the index to all occurrence's of the find text within the source text, after the specified search starting position.
Option Strict On
Public Class Form1
''' <summary>
''' Returns an array of indexes where the find text occurred in the source text.
''' </summary>
''' <param name="Source">The text you are searching.</param>
''' <param name="Find">The text you are searching for.</param>
''' <param name="StartIndex"></param>
''' <returns>Returns an array of indexes where the find text occurred in the source text.</returns>
''' <remarks></remarks>
Function FindInString(Source As String, Find As String, StartIndex As Integer) As List(Of Integer)
If StartIndex > Source.Length - Find.Length Then Return New List(Of Integer)
If StartIndex < 0 Then Return New List(Of Integer)
If Find.Length > Source.Length Then Return New List(Of Integer)
Dim Results As New List(Of Integer)
For I = StartIndex To (Source.Length) - Find.Length
Dim TestString As String = String.Empty
For II = I To I + Find.Length - 1
TestString = TestString & Source(II)
Next
If TestString = Find Then Results.Add(I)
Next
Return Results
End Function
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
Dim Search As String = "Hello world, this world is an interesting world"
Dim Find As String = "world"
Dim Indexes As List(Of Integer) = New List(Of Integer)
Try
Indexes = FindInString(Search, Find, 0)
Catch ex As Exception
MsgBox(ex.ToString)
End Try
RichTextBox1.Text = "Search:" & vbCrLf
RichTextBox1.Text = RichTextBox1.Text & Search & vbCrLf & vbCrLf
RichTextBox1.Text = RichTextBox1.Text & "Find:" & vbCrLf
RichTextBox1.Text = RichTextBox1.Text & Find & vbCrLf & vbCrLf
RichTextBox1.Text = RichTextBox1.Text & "-----------" & vbCrLf
RichTextBox1.Text = RichTextBox1.Text & "Result Indexes:" & vbCrLf & vbCrLf
For Each i As Integer In Indexes
RichTextBox1.Text = RichTextBox1.Text & i.ToString & vbCr
Next
Catch ex As Exception
MsgBox(ex.ToString)
End Try
End Sub
End Class
Here is another way, where there is no use of .Net functions.
Function FindInString(Source As String, Find As String, StartIndex As Integer) As Integer()
If StartIndex > Len(Source) - Len(Find) Then Return {}
If StartIndex < 0 Then Return {}
If Len(Find) > Len(Source) Then Return {}
Dim Results As Integer() = {}, ResultCount As Integer = -1
For I = StartIndex To Len(Source) - Len(Find)
Dim TestString As String = ""
For II = I To I + Len(Find) - 1
TestString = TestString & Source(II)
Next
If TestString = Find Then
ResultCount += 1
ReDim Preserve Results(ResultCount)
Results(ResultCount) = I
End If
Next
Return Results
End Function
How to remove the last element from an array in VB.NET. I need to split the street and housenumber.
STREET
Split the address on spaces
Remove last element (missing in the code)
Join array
NUMBER
Split the address on spaces
get last element
My code:
'split address
Dim addressArray() As String = args.Content.Split(" ")
'remove last element and return the joined array
Return String.Join(" ", addressArray.Remove(addressArray.Length() - 1))
Dim foo() As String = "This is a test".Split(New Char() {" "c}, StringSplitOptions.RemoveEmptyEntries)
Array.Resize(foo, foo.Length - 1)
Dim s As String = String.Join(" ", foo)
or use lists
Dim foo As New List(Of String)
foo.AddRange("This is a test".Split(New Char() {" "c}, StringSplitOptions.RemoveEmptyEntries))
foo.RemoveAt(foo.Count - 1)
Dim s As String = String.Join(" ", foo)
As far as using LINQ and performance, judge for yourself
Public Class Form1
'to LINQ or not to LINQ
'judge for yourself
Dim stpw As New Stopwatch
Private Sub Button1_Click(sender As System.Object, _
e As System.EventArgs) Handles Button1.Click
Dim ipsumA() As String = New String() {"Lorem", "ipsum", "dolor", "sit", _
"amet", "consectetur", "adipisicing", _
"elit", "sed", "do", "eiusmod", _
"tempor", "incididunt", "ut", "labore", _
"et", "dolore", "magna", "aliqua", "Ut", _
"enim", "ad", "minim", "veniam", "quis", _
"nostrud", "exercitation", "ullamco", _
"laboris", "nisi", "ut", "aliquip", "ex", _
"ea", "commodo", "consequat", "Duis", "aute", _
"irure", "dolor", "in", "reprehenderit", "in", _
"voluptate", "velit", "esse", "cillum", "dolore", _
"eu", "fugiat", "nulla", "pariatur", "Excepteur", _
"sint", "occaecat", "cupidatat", "non", "proident", _
"sunt", "in", "culpa", "qui", "officia", "deserunt", _
"mollit", "anim", "id", "est", "laborum"}
Const tries As Integer = 100000
Debug.WriteLine("")
stpw.Reset()
stpw.Start()
For x As Integer = 1 To tries
Dim s As String = arrayTake(ipsumA)
Next
stpw.Stop()
Debug.WriteLine(stpw.ElapsedTicks.ToString)
stpw.Reset()
stpw.Start()
For x As Integer = 1 To tries
Dim s As String = arrayRsz(ipsumA)
Next
stpw.Stop()
Debug.WriteLine(stpw.ElapsedTicks.ToString)
End Sub
Private Function arrayRsz(test As String()) As String
Array.Resize(test, test.Length - 1)
Return String.Join(" ", test)
End Function
Private Function arrayTake(test As String()) As String
Return String.Join(" ", test.Take(test.Length - 1))
End Function
End Class
You can't remove items from an array. The size of an array is decided when you create it, and can't be changed.
You can create a result that contains the items from the array except the last one:
Return String.Join(" ", addressArray.Take(addressArray.Length() - 1))
Edit:
If you are concerned about performance, you should not do any Split or Join at all, but simply get the parts of the string using simple string operations:
Dim pos As Integer = args.Content.LastIndexOf(" "C)
Dim street As String = args.Content.Substring(0, pos)
Dim number As String = args.Content.Substring(pos + 1)
This is at least ten times faster than any other method presented here.
Edit 2:
Here is the performance test code (C#):
Dim time As Performance = New Performance(1000000, 6)
Dim address As String = "aölskdjf öawe öofij 42"
Console.WriteLine(time.Take("SplitTakeJoin", Sub()
Dim parts As String() = address.Split(" "c)
Dim street As String = String.Join(" ", parts.Take(parts.Length - 1))
End Sub))
Console.WriteLine(time.Take("SplitResizeJoin", Sub()
Dim parts As String() = address.Split(" "c)
Array.Resize(parts, parts.Length - 1)
Dim street As String = String.Join(" ", parts)
End Sub))
Console.WriteLine(time.Take("Substring", Sub()
Dim street As String = address.Substring(0, address.LastIndexOf(" "c))
End Sub))
Output:
SplitTakeJoin 0,000511 ms.
SplitResizeJoin 0,000323 ms.
Substring 0,000031 ms.
using this performance test class:
Public Class Performance
Private _iterations As Integer
Private _displayDigits As Integer
Private _emptyTime As TimeSpan
Public Sub New(ByVal iterations As Integer, ByVal displayDigits As Integer)
_iterations = iterations
_displayDigits = displayDigits
_emptyTime = TimeSpan.Zero
_emptyTime = Take(Sub()
End Sub)
End Sub
Private Function Take(ByVal action As Action) As TimeSpan
Dim w As Stopwatch = Stopwatch.StartNew()
For i As Integer = 0 To _iterations - 1 Step 10
Action()
Action()
Action()
Action()
Action()
Action()
Action()
Action()
Action()
Action()
Next
w.Stop()
Return w.Elapsed - _emptyTime
End Function
Public Function Take(ByVal title As String, ByVal action As Action) As String
Dim Time As TimeSpan = Take(action)
Return title + " " + (Time.TotalMilliseconds / Convert.ToDouble(_iterations)).ToString("N" + _displayDigits.ToString()) + " ms."
End Function
End Class
You could also try using Redim Preserve. These statements are carry overs from the Visual Basic 6.0 days and are not considered the .NET way of doing things, but it is another option. There may be performance issues though according to this article.
Redim Preserve addressArray(addressArray.Length - 1)
Actually to delete the last item of array you would have to:
Redim Preserve addressArray(addressArray.Length - 2)
since they are zero based and the length is one based.
This will return all but the last "word/number" in a String as an array of Strings.
Return args.content.Split(" ").Take((args.content.Split(" ").Count - 1)).ToArray()
I have a xls file, or a csv without quotes, and using vb.net need to turn it into a csv with quotes around every cell. If I open the xls/csv without quotes in MS Access, set every column to text and then export it, its in the format I need. Is there an easier way? If not, how do I do replicate this in vb.net? Thanks.
If you use the .Net OLE DB provider, you can specify the .csv formatting details in a schema.ini file in the folder your data files live in. For the 'unquoted' .csv the specs
should look like
[noquotes.csv] <-- file name
ColNameHeader=True <-- or False
CharacterSet=1252 <-- your encoding
Format=Delimited(,) <--
TextDelimiter= <-- important: no " in source file
Col1=VendorID Integer <-- your columns, of course
Col2=AccountNumber Char Width 15
for the 'quoted' .csv, just change the name and delete the TextDelimiter= line (put quotes around text fields is the default).
Then connect to the Text Database and execute the statement
SELECT * INTO [quotes.csv] FROM [noquotes.csv]
(as this creates quotes.csv, you may want to delete the file before each experimental run)
Added to deal with "Empty fields must be quoted"
This is a VBScript demo, but as the important things are the parameters for .GetString(), you'll can port it to VB easily:
Dim sDir : sDir = resolvePath( "§LibDir§testdata\txt" )
Dim sSrc : sSrc = "noquotes.csv"
Dim sSQL : sSQL = "SELECT * FROM [" & sSrc & "]"
Dim oTxtDb : Set oTxtDb = New cADBC.openDb( Array( "jettxt", sDir ) )
WScript.Echo goFS.OpenTextFile( goFS.BuildPath( sDir, sSrc ) ).ReadAll()
Dim sAll : sAll = oTxtDb.GetSelectFRO( sSQL ).GetString( _
adClipString, , """,""", """" & vbCrlf & """", "" _
)
WScript.Echo """" & Left( sAll, Len( sAll ) - 1 )
and output:
VendorID;AccountNumber;SomethingElse
1;ABC 123 QQQ;1,2
2;IJK 654 ZZZ;2,3
3;;3,4
"1","ABC 123 QQQ","1,2"
"2","IJK 654 ZZZ","2,3"
"3","","3,4"
(german locale, therefore field separator ; and decimal symbol ,)
Same output from this VB.Net code:
Imports ADODB
...
Sub useGetString()
Console.WriteLine("useGetString")
Const adClipString As Integer = 2
Dim cn As New ADODB.Connection
Dim rs As ADODB.Recordset
Dim sAll As String
cn.ConnectionString = _
"Provider=Microsoft.Jet.OLEDB.4.0;" _
& "Data Source=M:\lib\kurs0705\testdata\txt\;" _
& "Extended Properties=""text;"""
cn.Open()
rs = cn.Execute("SELECT * FROM [noquotes.csv]")
sAll = rs.GetString( adClipString, , """,""", """" & vbCrLf & """", "" )
cn.Close()
sAll = """" & Left( sAll, Len( sAll ) - 1 )
Console.WriteLine( sAll )
End Sub
Check out the method at this link.
What you can do to make sure quotes go around is append quotes to the beginning and end of each column data in the loop that is putting the column data in the file.
for example make the loop like this:
For InnerCount = 0 To ColumnCount - 1
Str &= """" & DS.Tables(0).Rows(OuterCount).Item(InnerCount) & ""","
Next
Public Class clsTest
Public Sub Test
Dim s as string = "C:\!Data\Test1.csv"
Dim Contents As String = System.IO.File.ReadAllText(s)
Dim aryLines As String() = Contents.Split(New String() { Environment.Newline }, StringSplitOptions.None)
Dim aryParts() As String
Dim aryHeader() As String
Dim dt As System.Data.DataTable
For i As Integer = 0 To aryLines.Length - 1
aryParts = SplitCSVLine(aryLines(i))
If dt Is Nothing And aryHeader Is Nothing Then
aryHeader = CType(aryParts.Clone, String())
ElseIf dt Is Nothing And aryHeader IsNot Nothing Then
dt = DTFromStringArray(aryParts, 1000, "", aryHeader)
Else
DTAddStringArray(dt, aryParts)
End If
Next
dt.dump
End Sub
Public Shared Function SplitCSVLine(strCSVQuotedLine As String) As String()
Dim aryLines As String() = strCSVQuotedLine.Split(New String() {Environment.NewLine}, StringSplitOptions.None)
Dim aryParts As String() = Nothing
For i As Integer = 0 To aryLines.Length - 1
Dim regx As New Text.RegularExpressions.Regex(",(?=(?:[^\""]*\""[^\""]*\"")*(?![^\""]*\""))")
aryParts = regx.Split(aryLines(i))
For p As Integer = 0 To aryParts.Length - 1
aryParts(p) = aryParts(p).Trim(" "c, """"c)
Next
Next
Return aryParts
End Function
Public Shared Function DTFromStringArray(ByVal aryValues() As String, Optional ByVal intDefaultColumnWidth As Integer = 255, Optional ByVal strTableName As String = "tblArray", Optional ByVal aryColumnNames() As String = Nothing) As DataTable
If String.IsNullOrWhiteSpace(strTableName) Then strTableName = "tblArray"
Dim dt As DataTable = New DataTable(strTableName)
Dim colNew(aryValues.GetUpperBound(0)) As DataColumn
If aryColumnNames Is Nothing Then
ReDim aryColumnNames(aryValues.Length)
Else
If aryColumnNames.GetUpperBound(0) < aryValues.GetUpperBound(0) Then
ReDim Preserve aryColumnNames(aryValues.Length)
End If
End If
For x As Integer = aryColumnNames.GetLowerBound(0) To aryColumnNames.GetUpperBound(0)
If String.IsNullOrWhiteSpace(aryColumnNames(x)) Then
aryColumnNames(x) = "Field" & x.ToString
Else
aryColumnNames(x) = aryColumnNames(x)
End If
Next
For i As Integer = 0 To aryValues.GetUpperBound(0)
colNew(i) = New DataColumn
With colNew(i)
.ColumnName = aryColumnNames(i) '"Value " & i
.DataType = GetType(String)
.AllowDBNull = False
.DefaultValue = ""
.MaxLength = intDefaultColumnWidth
.Unique = False
End With
Next
dt.Columns.AddRange(colNew)
Dim pRow As DataRow = dt.NewRow
For i As Integer = aryValues.GetLowerBound(0) To aryValues.GetUpperBound(0)
pRow.Item(i) = aryValues(i)
Next
dt.Rows.Add(pRow)
Return dt
End Function
Public Shared Sub DTAddStringArray(ByRef dt As DataTable, ByVal aryRowValues() As String)
Dim pRow As DataRow
pRow = dt.NewRow
For i As Integer = aryRowValues.GetLowerBound(0) To aryRowValues.GetUpperBound(0)
pRow.Item(i) = aryRowValues(i)
Next
dt.Rows.Add(pRow)
End Sub
End Class