One approach would be to "take a snapshot" of the universe and store that screenshot to disk. In other words we'd like the disk file to be a picture of the universe. If the universe looks like this onscreen,
- - - - - - - @ - - - - - @ - - @ @ @ - - - - - -
We'd like to store this in the file,
- - - - - \n- - @ - - \n- - - @ - \n- @ @ @ - \n- - - - - \nEOF
We can do that by copying our original display code and modifying it to open a file and
then use write instead of print.
One nice thing about this representation is that it could be opened in a text editor and modified to create new starting configurations for the universe. It's always nice if your file format plays well with the other tools you are using.
The resulting code to write the universe to disk in this format looks much like the
code to display it onscreen, but has to open the file and then use
write instead of print for output.
fname = raw_input('Name of file to store universe in: ')
outfile = open(fname, 'w')
for row in range(u_rows):
for col in range(u_cols):
if u[row][col] == 1:
outfile.write(LIVE_CELL+' ')
elif u[row][col] == 0:
outfile.write(DEAD_CELL+' ')
outfile.write('\n')
outfile.close()How is this format?
It is easy to write the code to write it to disk.
You will have to evaluate how easy it is to write code to read it from disk once you have completed the assignment.
How about the size of the representation on disk? For each cell in the universe it stores two Bytes to disk, one for the cell and one for the space separating it from the next cell. In addition it stores a newline character to mark the end of each row. So for an r × c universe it uses (r × c × 2) + r Bytes. To make this more concrete lets consider a couple of specific universe sizes:
| Universe size | Storage Space |
|---|---|
| 25 x 80 | 4,025 Bytes |
| 1000 x 1000 | 2,001,000 Bytes |
We could cut the storage almost in half just by dropping the spaces we store to disk. Does this make it easier to harder to read the file in from disk? If it makes it harder, is it worth it?