I am trying to parse a file using regex split, it works well with the '\t' character but some lines have the '\t' inside a field instead of acting as the delimiter.
Like :
G2226 TEST 1 C 29 Internal Head Office D Head Office ZZZ Unassigned 10910 10/10/2011 11/10/2011 10/10/2011 11/10/2011 "Test call Sort the customer out some data. See the customer again tomorrow to talk about Prod " Mr ABC Mr ABC Mr ABC Mr ABC Credit Requested BDM Call Internal Note 10
This part has 2 tabs I wish were ignored :
"Test call Sort the customer out some data. See the customer again tomorrow to talk about Prod\t\t"
The good thing is, they are included in double quotes, but I cannot work out how to ignore them, any ideas?
Edit:
My goal is to get 36 columns, some columns may come out more after a Regex.Split(lineString,'\t') using '\t' because they include '\t' characters inside some of the fields. I would like to ignore those ones. The one above comes out to 38 cols, which is rejected by my datatable as the header is only 36 cols, I would like to solve this problem.
If you have a simple CSV file, then regex split is usually the easiest way to process it.
However, if your CSV file contains more complex elements, such as quoted fields that contain separator characters or newlines, then this approach will no longer work. It is not a trivial matter to correctly parse these types of files, so you should use a library when possible.
The answers to this question give several options for C# libraries that can read a CSV file.
Regex is not the right tool for this.
You have basically a CSV format, it is "tab separated", not "comma separated", but it works exactly the same. So, find a CSV parser and use that - the separation character is usually configurable.
If you really need a regular expression, you can try something like this:
(?!\t")\t(?!\t")
Related
This is likely a very basic question that I could not, despite trying, find a satsifying answer to. Feel free to skip to the question at the end if you aren't interested in the background.
The task:
I wish to create an easy localisation solution for my unity projects. After some initial research I concluded it would be best to use a .csv file read by a streamreader, so that translators would only ever have to interact with the csv table, where information is neatly organized.
The main problem:
Due to the nature of the text, I need to account for linebreaks and special characters in the actual fields. As such I could not use the normal readLine() method.
This I worked with by using Read() and checking if a linebreak is within a text delimiter bracket. But as I check for the text delimiter, I am afraid it might run into an un-escaped delimiter part of the normal in-cell text (since the normal text delimiter is quotation marks).
So I switched the delimiter to §. But now every time I open the file I have to re-enter § as a text delimiter in OpenOfficeCalc, probably due to encoding differences. Which is annoying but not the end of the world.
My question:
How does OpenOffice (or similar software) usually tell in-cell commas/quotation marks apart from the ones used as delimiters? If I knew that, I could probably incorporate a similar approach in my reading of the file.
I've tried to look at the files with NotePad++, revealing a difference in linebreaks (/r instead of /r/n) and obviously it's within a text delimiter bracket, but when it comes to how it seperates its delimiters from ones just entered in the text/field, I am drawing a blank.
Translation file in OpenOffice Calc:
Translation file in NotePad++, showing all characters:
I'd appreciate any insight or links on the topic.
From https://en.wikipedia.org/wiki/Comma-separated_values:
The CSV file format is not fully standardized. The basic idea of separating fields with a comma is clear, but that idea gets complicated when the field data may also contain commas or even embedded line breaks.
LibreOffice Calc has a reasonable way to handle these things.
Use LF for line breaks and CR at the end of each record. It seems your code already handles this.
Use quotes to delimit strings when needed. If the string contains one or more quotes, then duplicate the quote to make it literal.
From the example in your question, it looks like you told Calc not to use any quotes as string delimiters. Why did you do this? When I tried it, LibreOffice (or Apache OpenOffice) showed the fields in different columns after opening the file saved that way.
The following example CSV file has fields that contain commas, quotes and line breaks.
When viewed in Calc:
A B
--------- --
1 | 1,",2", 3
--------- --
2 | a c
| b
Calc correctly reads and saves the file as shown below. Settings when saving are Field delimiter , and String delimiter " which are the defaults.
"1,"",2"",",3[CR]
"a
b",c[CR]
I have 2 types of input files:
1. comma delimited (i.e: lastName, firstName, Address)
2. space delimited (i.e lastName firstName Address)
The comma delimited file HAS spaces between the ',' and the next word.
How do I go about determining which file I am dealing with ?
I am using C# btw
I've done tons of work with various delimited file types and as everyone else is saying, without normalization you can't really handle the whole thing programmatically.
Generally (and it seems like it would be totally necessary for space-delim) a delimited file will have a text qualifier character (often double-quotes). A couple examples of this points:
Space Delimited:
lastName "Von Marshall" is impossible
without qualifiers.
Addresses would be altogether impossible as well.
Comma Delimited:
addresses are generally unworkable unless they are broken into separate fields or having a solid string is acceptable for your use-case.
So the space delim should be easy enough to determine since you're looking for " ". If this is the case I'd (personally) replace all " " with "," to change it to comma-delim. That way you'd only have to build a single method for handling the text, otherwise I imagine you'll need methods for spaces and commas separately.
If your comma-delim file does not have a text qualifier, you're in a really tricky spot. I haven't found any "perfect" way of addressing this without any human work, but it can be minimized. I've used Notepad++ a lot to do batch replacement with its regular expression functions.
However, you can also use C#'s regex abilities. Here's what MSDN says on that.
So, to answer your question to the best of my ability, unless you can establish a uniqueness between the 2 file types - there's no way. However, if the text has proper text qualifiers, the files have different file extensions, or if the are generated in different directories - you could use any of those qualities or a mix thereof to decide what type of file it is. I have no experience doing this as yet (though I've just started a project using it), so I can't give an exact example, but I can say for anyone to build a perfect example it'd be best if you showed example strings for each file.
As other users have said with some guaranty of having no commas in the space delimited version you cannot with 100% accuracy.
With some information, say that there will always be three fields for all records in all cases when parsed correctly you could just do both and test the results for the correct number of fields. Address is a big block here though since we do not know what that format could be. Also these rules seems odd at best when talking about address.... is
1111somestreest.houston,tx11111 or
1111 somestreet st. Houston, Tx 11111
a valid format?
You could count the number of commas per line of the file. If you have at least 2 commas per line (considering your info is last name, first name, address), you probably have a comma separated. If you have, in at least one line, less than 2 commas, you should consider it as space separated.
I, however, would skip this step and ignore the commas when evaluating the input by replacing all of them by spaces and would implement a single read/grab information procedure (considering only space separated files).
I am having an issue with importing a CSV file. The problem arises when an address field has multiple comma seperated values e.g. home no, street no, town etc.
I tried to use http://forums.asp.net/t/1705264.aspx/1 this article but, the problem did not solved because of a single field containing multiple comma separated values.
Any idea or solution? because I didnt found any help
Thanks
Don't split the string yourself. Parsing CSV files is not trivial, and using str.Split(',') will give you a lot of headaches. Try using a more robust library like CsvHelper
- https://github.com/JoshClose/CsvHelper
If that doesn't work then the format of the file is probably incorrect. Check to make sure the text fields are properly quoted.
Do you control the format of the CSV file? You could see about changing it to qualify the values by surrounding them with double quotes (""). Another option is to switch to a different delimiter like tabs.
Barring that, if the address is always in the same format, you could read in the file, and then inspect each record and manually concatenate columns 2, 3, and 4.
Are the fields surrounded by quotation marks? If so, split on "," rather than just ,.
Is the address field at the beginning or end of a record? If so, you can ignore the first x commas (if at the beginning) or split only the correct number of fields (if at the end).
Ideally, if you have control of the source file's creation, you would change the delimiter of either the address sub-fields, or the record fields.
I have a CSV file, with the following type of data:
0,'VT,C',0,
0,'C,VT',0,
0,'VT,H',0,
and I desire the following output
0
VT,C
0
0
C,VT
0
0
VT,H
0
Therefore splitting the string on the comma however ignoring the comma within quote marks. At the moment I'm using the following RegEx:
("(?:^|,)(\"(?:[^\"]+|\"\")*\"|[^,]*)"
however this gives me the result of:
0
VT
C
0
0
C
VT
0
0
VT
H
0
This show the RegEx is not reading the quote mark properly. Can anyone suggest some alterations that might help?
Usually when it comes to CSV parsing, people use specific libraries well suited for the programming language they are using to code their application.
Anyway if you are going to use a regular expression to make a really loose(!) parsing you may try using something like this:
'(?<value>[^']*?)'
It will match anything in between single quotes, and assuming the csv file is well formed, it will not miss a field. Of course it doesn't accept embedded quotes but it easily gets the job done. That's what I use when I need to get the job done really quickly. Please don't consider it a complete solution to your problem...it just works in special conditions when the requirements are what you described and the input is well formed.
[EDIT]
I was checking again your question and noticed you want to include also non quoted fields...well ok in that case my expression will not work at all. Anyway listen...if you think hard about your problem, you'll find that's something quite difficult to solve without ambiguity. Because you need fixed rules and if you allow quoted and not quoted fields, the parser will have hard time figuring out legit commas as separator/quoted.
Another expression to model such a solution may be:
('[^']+'|[^,]+),?
It will match both quoted/notquoted fields...anyway I'm not sure if it needs to assume the csv HAS to adhere to strict conditions. That will work much safer then a split strategy as far as I can tell ... you just need to collect all matches and print the matched_value + \r\n on your target string.
This regex is based of the fact you have 1 digit before and after your 'value'
Regex.Replace(input, #"(?:(?<=\d),|,(?=\d))", "\n");
You can test it out on RegexStorm
foreach(var m in Regex.Matches(s,"(('.*?')|[0-9])"))
I have manages to get the following method to read the file as required:
public List<string> SplitCSV(string input, List<string> line)
{
Regex csvSplit = new Regex("(([^,^\'])*(\'.*\')*([^,^\'])*)(,|$)", RegexOptions.Compiled);
foreach (Match match in csvSplit.Matches(input))
{
line.Add(match.Value.TrimStart(','));
}
return line;
}
Thanks for everyone help though.
So Im reading a csv file and splitting the string with "," as the deliminator
but some of them have quotes as to not split the specific field because it has a comma in it.
1530,Pasadena CA,"2008, 05/01","2005, 12/14"
with just comma it would be:
1530
Pasadena CA
"2008
05/01"
"2005
12/14"
I need it to take commas into consideration when splitting so its like this
1530
Pasadena CA
"2008 05/01"
"2005 12/14"
Take a look at this page for a library that offers quick and easy CSV reading.
While it still may be a new reference, there is a class within the Visual Basic assemblies that should handle this well. At least then you know it's a part of the framework. You can find details here: http://msdn.microsoft.com/en-us/library/microsoft.visualbasic.fileio.textfieldparser.aspx