On 8/8/2022 4:47 AM, Andreas Croci wrote:
tI would like to write a program, that reads from the network a fixed
amount of bytes and appends them to a list. This should happen once a
second.
Another part of the program should take the list, as it has been
filled so far, every 6 hours or so, and do some computations on the
data (a FFT).
Every so often (say once a week) the list should be saved to a file,
shorthened in the front by so many items, and filled further with the
data coming fom the network. After the first saving of the whole list,
only the new part (the data that have come since the last saving)
should be appended to the file. A timestamp is in the data, so it's
easy to say what is new and what was already there.
I'm not sure how to do this properly: can I write a part of a program
that keeps doing its job (appending data to the list once every
second) while another part computes something on the data of the same
list, ignoring the new data being written?
Basically the question boils down to wether it is possible to have
parts of a program (could be functions) that keep doing their job
while other parts do something else on the same data, and what is the
best way to do this.
You might be able to do what you need by making the file system work for
you:
Use numbered files, something like DATA/0001, DATA/0002, etc.
Start by initializing a file number variable to 1 and creating an empty
file, DATA/0001. The current time will be your start time.
In an infinite loop, just as in Stefan's example:
Read from the network and append to the current data file. This
shouldn't take long unless the file is on a remote system.
If six hours have gone by (compare the current time to the start time),
close the current date file, create a thread (see Stefan's example) to
call your FFT with the name of the current file, increment the file
number, and open a new empty data file.
If you want to, you can consolidate files every week or so. The Python
library has functions that will let you get a list files in a directory.
If you're on a Linux or UNIX system, you can use shell commands to
append, copy or rename files.
Have fun.
Louis
--
https://mail.python.org/mailman/listinfo/python-list
