NSString *str = @"mario's test";
NSString *stringWithoutSpaces = [str stringByReplacingOccurrencesOfString:@" " withString:@""];

stringWithoutSpaces = "mariostest"

*stringWithoutSpaces = [[str stringByReplacingOccurrencesOfString:@" " withString:@""]
                             stringByReplacingOccurrencesOfString:@"'" withString:@""];