Passwords, can they be near unbreakable?

Got a question. I know a few basic things about encryption, like how they say you need to make a password lengthy, use numbers, symbols and upper and lower case letters. But isn't password length essentially the most useful? For example, what if I made a password 50 characters, but all just 123 repeated? It's 50 characters long. Wouldn't it take ages for even a powerful computer to crack it?

See, I'm wondering why it matters if you have symbols/case changes or not. Doesn't a computer simply try one a time, regardless of what it actually is? Like 123 is the same to a computer as !5E, isn't it?

Do partial matches and patterns register when searching? Or does it need the entire password at once to get through? If so, length seems like the only important thing.

Another option. Couldn't you just create an insanely bizarre 120 character password and then copy and paste it? Assuming no keyloggers catch it, that would keep every (human) out, because you could easily hide it in a mix of other random numbers in another file. It could be a box of code hundreds of lines long, and to find it you just look for the starting 3 numbers or something and copy and paste from there.

It's mostly a curiosity thing, but I wonder if these methods would work.

>>2
Thank you for the reply. I'm still not clear though on how the computer can tell if my password is made of simply letters/numbers, or if it has symbols included. So therefore it has to try all of them, right? That's what I meant by being the same.

In other words a computer (or person for that matter) doesn't know beforehand what you decided to use, so they may try numbers first, but that's just a guess. And if there's 50 of them? They can assume it's made of 1's and 2's, or it could be every key on my keyboard, and a few accented characters as well. Either way it has to start from scratch and go one by one, right?

Thanks again. This is neat stuff.