split NSString using componentsSeparatedByString - objective-c

Question

I have a string I need to split. It would be easy using componentsSeparatedByString but my problem is that the separator is a comma but I could have commas that aren't separator.
I explain:
My string:
NSString *str = #"black,red, blue,yellow";
the comma between red and blue must not be considered as separator.
I can determine if comma is a separator or not checking if after it there is a white space.
The goal is to obtain an array with:
(
black,
"red, blue",
yellow
)

Answer 1

This is tricky. First replace all occurences of ', ' (comma+space) with say '|' then use components separated method. Once you are done, again replace '|' with ', ' (comma+space).

Answer 2

Just to complete the picture, a solution that uses a regular expression to directly identify commas not followed by white space, as you explain in your question.
As others have suggested, use this pattern to substitute with a temporary separator string and split by that.
NSString *pattern = #",(?!\\s)"; // Match a comma not followed by white space.
NSString *tempSeparator = #"SomeTempSeparatorString"; // You can also just use "|", as long as you are sure it is not in your input.
// Now replace the single commas but not the ones you want to keep
NSString *cleanedStr = [str stringByReplacingOccurrencesOfString: pattern
withString: tempSeparator
options: NSRegularExpressionSearch
range: NSMakeRange(0, str.length)];
// Now all that is needed is to split the string
NSArray *result = [cleanedStr componentsSeparatedByString: tempSeparator];
If you are not familiar with the regex pattern used, the (?!\\s) is a negative lookahead, which you can find explained quite well, for instance here.

Answer 3

Here is coding implementation for cronyneaus4u's solution:
NSString *str = #"black,red, blue,yellow";
str = [str stringByReplacingOccurrencesOfString:#", " withString:#"|"];
NSArray *wordArray = [str componentsSeparatedByString:#","];
NSMutableArray *finalArray = [NSMutableArray array];
for (NSString *str in wordArray)
{
str = [str stringByReplacingOccurrencesOfString:#"|" withString:#", "];
[finalArray addObject:str];
}
NSLog(#"finalArray = %#", finalArray);

Answer 4

NSString *str = #"black,red, blue,yellow";
NSArray *array = [str componentsSeparatedByString:#","];
NSMutableArray *finalArray = [[NSMutableArray alloc] init];
for (int i=0; i < [array count]; i++) {
NSString *str1 = [array objectAtIndex:i];
if ([[str1 substringToIndex:1] isEqualToString:#" "]) {
NSString *str2 = [finalArray objectAtIndex:(i-1)];
str2 = [NSString stringWithFormat:#"%#,%#",str2,str1];
[finalArray replaceObjectAtIndex:(i-1) withObject:str2];
}
else {
[finalArray addObject:str1];
}
}
NSLog(#"final array count : %d description : %#",[finalArray count],[finalArray description]);
Output:
final array count : 3 description : (
black,
"red, blue",
yellow
)