[Tutor] A file containing a string of 1 billion random digits.

[Richard D. Moores]

On Sat, Jul 17, 2010 at 11:06, Alan Gauld <alan.gauld at btinternet.com> wrote:
>
> "Richard D. Moores" <rdmoores at gmail.com> wrote
>
>> amount of memory my laptop has (4 GB). So my question is, how can I do
>> this differently? I'm pretty brand new to opening and writing files.
>> Here, I can't write many shorter lines, because the end result I seek
>> is one long string. But am I correct?
>
> Others have answered that but I will ask, have you considered what
> you will do with this 4G string once you have created it?

Windows Explorer tells me it is 976,563 KB.

> You will not
> be able to read it back into your memory in one piece so you will
> need to process it in chunks.

Yes, that's true. Here's what I'm doing with a 200-million-digit
string: <http://tutoree7.pastebin.com/rJ1naffZ>. But this script with
a 500 million string already causes a memory problem, and 1 billion is
impossible. If I processed in chunks, they would need to overlap
slightly, because the sequences to be found, such as 05251896 (my
father's birth date) could overlap the boundary between 2 neighboring
chunks, and thus not be located. That's about as far as I've got in
thinking about the problem.

> It may be as well considering what you intend to do with it before
> creating it? There may be a better representation.

Now that you see what I want to do with 1 billion random digits,
please give me your suggestion(s). As I mentioned before, I'm very new
to reading from and writing to files.

I think the project is much more interesting/satisfying, though
technically almost identical, when locating sequences of digits in pi.
I have a 100-million-digit file for this (thanks to gmpy.pi()), but
haven't tried for anything bigger. Here's the script that handles
searches in the mantissa of pi:
<http://tutoree7.pastebin.com/3mqCNgQJ>. I've put the 1 million digits
of pi on my website in the Pi directory at <http://www.rcblue.com/Pi/>
should anyone want to try this out. I'm not sure what my downloading
limit is, so I may not leave the file up there more than 24 hours.

Dick