Hi, The below code is to get substrings from a string. You are going to love this below code which is very simple but very effective. I have used regular expression to get the sub strings.

NSString *strTest = @"Hii how are you doing @Ravi , how do u do @Kiran  where are you @Varun";
NSError *error;  
NSRegularExpression *exp =[NSRegularExpression regularExpressionWithPattern:@"@[^ ]*" options:NSRegularExpressionCaseInsensitive error:&error];
NSArray *s1= [exp matchesInString:strTest options:NSMatchingReportCompletion range:NSMakeRange(0, [strTest length]) ];
    [s1 enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        NSTextCheckingResult *result = obj;
        NSString *str = [strTest substringWithRange:result.range];
        NSLog(@"str %@",str);

    }];