Splitting string quotation mark errors - vb.net

Question

tl:dr
How can I programatically flag a quotation mark (") when it is not a quote-comma (",) or a comma-quote (,")?
I am running a program that opens csv files, reads each line, then splits the line based on the location of the commas. There are enough text strings that have quotes in them, so I am using
filereader1.HasFieldsEnclosedInQuotes = True
However, when the files were created, there was no regard for having even numbers of quotes in the lines. Most of the time, it's not a big deal. There are only a couple of instances per folder of files.
But, I'm running into a few where it's a huge number. Dozens of instances in a file of several thousand lines. There isn't a simple way to manually error-check these.
So, I'm trying to do a verify that a string has rogue quotes. A comma-quote (,") or quote-comma ("), would be okay, but a quote (") just floating around would pull up an input box displaying the text line for manual fixes.
I can't use an odd number of quotes, because I've found even numbers of error quotes.
Below is the code as it stands.
Using filereader1 As New Microsoft.VisualBasic.FileIO.TextFieldParser(files_(i))
filereader1.TextFieldType = FieldType.Delimited
filereader1.Delimiters = New String() {","}
filereader1.HasFieldsEnclosedInQuotes = True
While Not filereader1.EndOfData
'While (filereader1.EndOfData = False) ' looks for the end of the file and resets stuff
split_string = filereader1.ReadFields()
This is something of what I am thinking.
I would like to run a readline instead of a readfield, and I would assign that to a variable. If the readline had a quote, but that could not be a quote-comma OR a comma-quote, the variable would get displayed in an input box for manual updating. Then the fixed variable would get parsed into the split_string array.
If the quotes all fit the rule above, the string would get parsed normally.

Answer 1

Could you do a count of the different type of strings in the readLine, and if the count of all quotes versus the sum of all ", and ," don't match, then you have an issue?
Public Function CountChar(originalString As String, findString As String) as Long
Dim lLen As Long = 0
Dim lCharLen As Long = 0
Dim lAns As Long = 0
Dim sChar As String = ""
Dim lCtr As Long = 0
Dim lEndOfLoop As Long = 0
lLen = Len(originalString)
lCharLen = Len(findString)
lEndOfLoop = (lLen - lCharLen) + 1
For lCtr = 1 To lEndOfLoop
sChar = Mid(originalString, lCtr, lCharLen)
If StrComp(sChar, findString, vbTextCompare) = 0 Then lAns = lAns + 1
Next
return lAns
End Function
Usage
'if the count of all quotes does not equal count of ", + ,", then there is an issue.
if CountChar(thisLine, chr(34)) <> (countChar(thisLine, chr(34) & ",") + countChar(thisLine, & "," & chr(34)) then
'rogue quotes
end if

Answer 2

So, this is what I ended up doing.
I read each line from the csv file.
I check to see how many quotes are in the line.
If the number is zero, I parse based on commas alone.
If there are an odd number of quotes, I eliminate ALL the quotes in the line, and send it to the manual error-checking.
If there are an even number of quotes, I replace the character string ," and ", with ::
Then I parse the line on both commas and ::
This seems to be working.
Using filereader As New Microsoft.VisualBasic.FileIO.TextFieldParser(files_(i), System.Text.Encoding.Default) 'system text decoding adds odd characters
While Not filereader.EndOfData
filereader.TextFieldType = FieldType.Delimited
'filereader.Delimiters = New String() {","}
filereader.SetDelimiters(",") 'tried new from Don's program 6/12
filereader.HasFieldsEnclosedInQuotes = True
filereader.TextFieldType = FieldType.Delimited
Try
'split_string = filereader1.ReadFields()
whole_string = filereader.ReadLine()
Catch ex As Microsoft.VisualBasic.FileIO.MalformedLineException
MessageBox.Show(ex.Message & " : " & FileName & " ; " & filereader.ErrorLine)
error_throw = filereader.ErrorLine
error_throw = error_throw.Replace("""", " ")
split_string = Split(error_throw, ",")
'MsgBox("In catch routine, split string (0) " & split_string(0))
End Try
Dim cnt As Integer = 0
Dim MyRegex As New Regex("""[^""]*""|(,)")
For Each c As Char In whole_string
If c = """" Then cnt = cnt + 1
Next
'MsgBox("cnt = " & cnt)
If cnt = 0 Then 'no quotes
split_string = Split(whole_string, ",") 'split by commas
'MsgBox("no quotes")
ElseIf cnt Mod 2 = 0 Then 'even number of quotes
Dim pattern1 As String = "\.?(,"")+"
Dim pattern2 As String = "\.?("",)+"
Dim rgex1 As New Regex(pattern1)
Dim rgex2 As New Regex(pattern2)
Dim replace1 As String = "::"
Dim replace2 As String = "::"
Dim whole_string1 As String = rgex1.Replace(whole_string, replace1)
Dim whole_string2 As String = rgex2.Replace(whole_string1, replace2)
whole_string1 = rgex1.Replace(whole_string, replace1)
whole_string2 = rgex2.Replace(whole_string1, replace2)
'MsgBox(whole_string & " >> " & whole_string1 & " >> " & whole_string2)
'split_string = Split(whole_string2, ",") 'non-regex code that allows program to run
split_string = Regex.Split(whole_string2, ",|([<::>+].*[<::>+])")
'(",(?=(?:[^\""]*\""[^\""]*\"")*(?![^\""]*\""))")
'MsgBox("Before " & split_string(0) & " | " & split_string(1) & " | " & split_string(2) & " | " & split_string(3) & " | " & split_string(4) & " | " & split_string(5) & " | " & split_string(6) & " | " & split_string(7))
Dim arraycount_2 As Integer = split_string.getupperbound(0)
For p = 0 To arraycount_2
split_string(p) = split_string(p).replace("::", "")
Next
'MsgBox("After " & split_string(0) & " | " & split_string(1) & " | " & split_string(2) & " | " & split_string(3) & " | " & split_string(4) & " | " & split_string(5) & " | " & split_string(6) & " | " & split_string(7))
ElseIf cnt Mod 2 <> 0 Then 'odd number of quotes
'MsgBox("Odd quotes")
whole_string = whole_string.Replace("""", " ") 'delete all quotes
split_string = Split(whole_string, ",") 'split by commas
Else
' MsgBox("no answer to ENTRY splitting of Whole_string")
End If