Split NSString preserving quoted substrings

Question

I need to split up a string which is separated by commas while preserving any quoted substrings (which may have commas too).

String example:

NSString *str = @"One,Two,\"This is part three, I think\",Four";
for (id item in [str componentsSeparatedByString:@","])
    NSLog(@"%@", item);

This returns:

• One
• Two
• "This is part three
• I think"
• Four

The correct result (respecting quoted substrings) should be:

• One
• Two
• "This is part three, I think"
• Four

Is there a reasonable way to do this, without re-inventing or re-writing quote-aware parsing routines?

Answer 1

Let's think about this a different way. What you have is a comma-seperated string, and you want the fields in the string.

There's some code for that:

https://github.com/davedelong/CHCSVParser

And you'd do this:

NSString *str = @"One,Two,\"This is part three, I think\",Four";
NSArray *lines = [str CSVComponents];
for (NSArray *line in lines) {
  for (NSString *field in line) {
    NSLog(@"field: %@", field);
  }
}

Answer 2

Here is a C# answer to the same problem.

C# Regex Split - commas outside quotes

You could probably use the same Regex in Objective-C

NSString split Regex with ,(?=(?:[^']*'[^']*')*[^']*$)