A nice and simple way to get the characters in-between a start character and an end character using NSRange. Replace cell.text with your string.

Setting parameters on an NSString (iOS)

NSString *param3 = nil;
NSRange start3 = [cell.text rangeOfString:@"thestartcharacterhere"];
if (start3.location != NSNotFound)
{
    param3 = [cell.text substringFromIndex:start3.location + start3.length];
    NSRange end3 = [param3 rangeOfString:@"theendcharacterhere"];
    if (end3.location != NSNotFound)
    {
        param3 = [param3 substringToIndex:end3.location];
    }
        
        NSLog(@"%@", param3);
}