example.md

The string ...

A,"B,","my Name is ""Alf"", hello",
,C,,

with the delimiter , becomes ...

[
    [
        "A",
        "B,",
        "my Name is \"Alf\", hello",
        "",
    ],
    [
        "",
        "C",
        "",
        ""
    ]
]

NSArray+LGCSVParser.h

#import <Foundation/Foundation.h>

@interface NSArray (LGCSVParser)

+ (instancetype)arrayWithCSVString:(NSString *)csvString delimiter:(unichar)delimiter;

@end

NSArray+LGCSVParser.m

#import "NSArray+LGCSVParser.h"

@implementation NSArray (LGCSVParser)

+ (instancetype)arrayWithCSVString:(NSString *)csvString delimiter:(unichar)delimiter
{
    // Field
    NSString * const fieldRegExPattern = [NSString stringWithFormat:@"(?<=^|%C)(\"(?:[^\"]|\"\")*\"|[^%C]*)", delimiter, delimiter]; // Via http://stackoverflow.com/questions/3268622/regex-to-split-line-csv-file - works very good. Handles double double quotes, fields containing a delimiter and starting and ending with double quotes, delimiter after double double quotes in field that starts and ends with double quotes.
    NSRegularExpression * const fieldRegEx = [NSRegularExpression regularExpressionWithPattern:fieldRegExPattern options:0 error:nil];
    
    // Quotes at start and end of string.
    NSRegularExpression * const quotesAtStartAndEndRegEx = [NSRegularExpression regularExpressionWithPattern:@"^\".+\"$" options:0 error:nil]; // Matches every string that starts and ends with double quotes and has something else in between.
    
    NSMutableArray *array = [NSMutableArray array];
    
    NSArray *lines = [csvString componentsSeparatedByString:@"\n"];
    for (NSString *line in lines) { // For each line ...
        NSMutableArray *lineArray = [NSMutableArray array]; // Will be filled with the fields.
        NSArray *fieldMatches = [fieldRegEx matchesInString:line options:0 range:NSMakeRange(0,[line length])]; // Matches every field.
        for (NSTextCheckingResult *fieldMatch in fieldMatches) { // Each field match ...
            NSMutableString *field = [NSMutableString stringWithString:[line substringWithRange:[fieldMatch range]]]; // Get field string.
            if ([quotesAtStartAndEndRegEx numberOfMatchesInString:field options:0 range: NSMakeRange(0, [field length])]) { // If field starts and ends with double quotes ...
                [field deleteCharactersInRange:NSMakeRange(0, 1)]; // Remove first ...
                [field deleteCharactersInRange:NSMakeRange([field length]-1, 1)]; //  ... and last char.
            }
            [field replaceOccurrencesOfString:@"\"\"" withString:@"\"" options:0 range:NSMakeRange(0, [field length])]; // Replace all double double quotes by single quotes.
            [lineArray addObject:field]; // Add final field string to line array.
        }
        [array addObject:lineArray]; // Add line array to array.
    }
    
    return array; // Return the array of arrays containing strings.
}

@end