Yes, you absolutely can leave an extra "." in the code and nothing bad will happen. The compiler will complain, you'll fix it, and then you move on.
More generally, I expect programmers I work with to know basic things like the language syntax. If you don't, learn them, and then you know them. I'd be surprised to see someone "working" in the industry if they can't get their code to compile.
The interesting stuff happens when you start using those tools to build things where there's no right or wrong answer. Being able to write code that runs is just a tool; the big question is "what can you do with it?" And if you keep the mindset that everything has to be perfect, you'll find yourself locked out of many of the interesting things you can do with computers.
More generally, I expect programmers I work with to know basic things like the language syntax. If you don't, learn them, and then you know them. I'd be surprised to see someone "working" in the industry if they can't get their code to compile.
The interesting stuff happens when you start using those tools to build things where there's no right or wrong answer. Being able to write code that runs is just a tool; the big question is "what can you do with it?" And if you keep the mindset that everything has to be perfect, you'll find yourself locked out of many of the interesting things you can do with computers.