How to split strings into substring start with some characters in ios

Question

I am stuck in finding the solution of splitting the string into substrings. I need some proper logic in which I need to read string starting with some character and it should contain at least 17 characters.

e.g. "43 01 08 43 13 01 18 FD 48 6B D1 43 01 22 02 01 02 02 F1 48 6B D1 43 02 03 03 51 03 52 75 48 6B D1 43 03 53 11 08 15 52 9D 48 6B D1 43 16 14 16 32 00 00"

For Above string , I need to split in into "43 01 08 43 13 01 18" "43 01 22 02 01 02 02" "43 02 03 03 51 03 52" "43 03 53 11 08 15 52" "43 16 14 16 32 00 00"

So On... I mean I need to get the position of "43" ,then from its index i Need to read 20 characters (Including space) and reject the characters until the next "43" appears (BOLD characters as mentioned above). Thanks in advance .. :)

I believe NSScanner is the best way to handle these kind of logic. — San
– San, Commented Nov 18, 2013 at 8:35
I was trying the sample code for pastebin.com/cHpGL1Gr but if there is any response which contains the "43" in between the string then it wont work !! — iCoder
– iCoder, Commented Nov 18, 2013 at 8:35
You said you need to read 20 chars from the '43', but in the example you provide, it seems you read only 10... — neutrino
– neutrino, Commented Nov 18, 2013 at 9:03

Arkku · Accepted Answer · 2013-11-18 15:02:26Z

3

I would just use rangeOfString: to locate the next 43, take the 20 characters from there on with substringWithRange:, and start over with the remaining substring (substringFromIndex:).

NSString *str = @"43 01 08 43 13 01 18 FD 48 6B D1 43 01 22 02 01 02 02 F1 48 6B D1 43 02 03 03 51 03 52 75 48 6B D1 43 03 53 11 08 15 52 9D 48 6B D1 43 16 14 16 32 00 00";
NSMutableArray *substrings = [NSMutableArray array];
NSRange range = { .length = 20 };
while ((range.location = [str rangeOfString:@"43"].location) != NSNotFound
       && str.length >= range.length + range.location) {
    [substrings addObject:[str substringWithRange:range]];
    str = [str substringFromIndex:range.location + range.length];
}

edited Nov 18, 2013 at 15:02

answered Nov 18, 2013 at 10:30

Arkku

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Comments

clevin · Accepted Answer · 2013-11-18 10:14:38Z

1

Try this:

   NSMutableArray *output = [[NSMutableArray alloc] init];
    NSString *allString = @"43 01 08 43 13 01 18 FD 48 6B D1 43 01 22 02 01 02 02 F1 48 6B D1 43 02 03 03 51 03 52 75 48 6B D1 43 03 53 11 08 15 52 9D 48 6B D1 43 16 14 16 32 00 00";

    while (allString.length>0) {
        [output addObject:[allString substringToIndex:20]];
        allString = [allString substringFromIndex:20];
        NSArray *arr = [allString componentsSeparatedByString:@"43"];

       if (arr.count>1){
          allString =@"43";
          for (int i=1;i<arr.count;i++){
              allString = [allString stringByAppendingString:[arr objectAtIndex:i]];
          }
       }else{
          allString=@"";
       }

    }

edited Nov 18, 2013 at 10:14

answered Nov 18, 2013 at 10:06

clevin

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Comments

Warren Burton · Accepted Answer · 2013-11-18 11:03:42Z

Assuming your sequence always starts with "43" and is seven items long.

Split the string and walk down the array creating sub arrays.

-(NSArray *)splitString:(NSString *)masterString
{
    NSArray *values = [masterString componentsSeparatedByString:@" "];

    NSMutableArray *outputarray = [@[] mutableCopy];

    NSUInteger marker = 0;

    NSString *startValue = @"43";

    NSUInteger subarraycount = 7;

    BOOL foundFlag = YES;

    while (foundFlag) {

        NSRange checkRange = NSMakeRange(marker, (values.count - marker));

        NSUInteger next = [values indexOfObject:startValue inRange:checkRange];

        foundFlag = (next != NSNotFound) && ((next + subarraycount) < values.count);

        if (foundFlag) {

            NSRange subrange = NSMakeRange(next, subarraycount);

            NSArray *subarray = [values subarrayWithRange:subrange];

            [outputarray addObject:[subarray componentsJoinedByString:@" "]];

            marker = next + subarraycount;
        }

    }

    return [outputarray copy];

}

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