Replacing character in a string

[E11esar]

Hi there.

I am looping through a csv file and for each line, I need to replace a comma in a string that occurs between quotes.

For example:

"The", "cat", "sat", "on, the", "mat"

Here I need to replace "on, the" with "on the".

My first draft solution is to count the quotes and if odd, the next comma is rogue. My first draft solution is as follows:

int quotesCount = 0;
for (int x = 0; x < line1.Length; x++)
{
if (line1[x] == (char)34) //quotes
{
quotesCount++;
}
if (line1[x] == (char)44) //comma
{
if ((quotesCount % 2 == 1) && (quotesCount > 1))
{
line1 = line1.Replace(line1[x], (char) 32); //replace comma with space character
}
}
}

This solution will replace all commas for a space character but I only want to replace the specific character for a given position value, here x.

Does anybody know how I can do this please?

Thank you.

M :)

[vekipeki]

String.Replace will replace all occurrences of a specified character with another character, so your line:

line1 = line1.Replace(line1[x], (char) 32);

is doing exactly that, replacing all commas with a space.

Since a String class is immutable (you cannot change it "in place"), consider using the StringBuilder Class (System.Text) and append character by character, while skipping the commas when needed.

[E11esar]

Another solution

Hi there.

I found another way to do this:

char[] tmpBuffer = line1.ToCharArray();
tmpBuffer[x] = (char)32;
line1 = new string(tmpBuffer);

Hopefully this may be of use to somebody else.

Thank you.

Mark :)

[Plater]

Are you doing something special that the comma cannot be there?
A comma inside a quote is part of the accepted CSV format.

Otherwise I guess what you're doing is going to work the best (some people suggest regex, but I have never found a CSV regex that ACTUALLY worked correctly)

[vekipeki]

If your actual problem is to parse a csv file, then why do you remove the commas first?

Just parse it on the fly, something like: find the opening quote, read all characters until you reach the closing quote (together with all the commas inside), then proceed to the next opening quote.

Right now you are looping through the whole thing twice, first time to remove the commas, second time to parse it, and at the end you don't have the commas (which are, as Plater said, accepted when put inside quotes).

[E11esar]

Are you doing something special that the comma cannot be there?
A comma inside a quote is part of the accepted CSV format.

Otherwise I guess what you're doing is going to work the best (some people suggest regex, but I have never found a CSV regex that ACTUALLY worked correctly)

Hi there. I need to use particular vales from within each line of the CSV file, so I have used a string.split() method so I can grasp the respective string array items and use them later to create the values in a sql WHERE clause.

I am hence finding that the split command is also splitting within a string enclosed betwen quotes.

Thank you.

M :)

[E11esar]

If your actual problem is to parse a csv file, then why do you remove the commas first?

Just parse it on the fly, something like: find the opening quote, read all characters until you reach the closing quote (together with all the commas inside), then proceed to the next opening quote.

Right now you are looping through the whole thing twice, first time to remove the commas, second time to parse it, and at the end you don't have the commas (which are, as Plater said, accepted when put inside quotes).

No at the moment I am splitting the file, by seperator equal to comma but that is not good, hence the commas are staying and I am removing the rogue commas using the method highlighted above. Hence just one pass is being made at a time.

Your idea of reading it in by way of quotes could be a good idea though...

Thank you.

Mark :)

[vekipeki]

If it works, then it's great.

Just note that

SELECT * FROM SomeTable
WHERE SomeColumn='a b c'

won't find columns where SomeColumn is 'a,b,c'.

[Plater]

If you plan to use SQL on it, have you considered opening the CSV file with oledb (using the Jet provider)?
that's what I do, it just reads it into a DataSet for me.