On 14Jun2018 16:54, Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info>
wrote:
On Thu, 14 Jun 2018 09:26:44 -0700, francois.rabanel wrote:
My problem is, if I work on a huge file, I'll try to avoid to read the
file because it will be crash my computer :)
How does reading a file crash your computer?
Likely because he tried to read the whole file into memory and match against
it. Guessing:
text = open(the_filename).read()
... search the text for the regexp ...
Francois, unless your regex can cross multiple lines it is better to search
files like this:
with open(the_filename) as f:
for line in f:
... search the line for the regexp ...
That way you only need to keep one line at a time in memory.
except OSError:
print("Permission denied")
That's not what OSError means. OSError can mean many different things.
That's why it isn't called "PermissionDeniedError".
You need to look at the exception to see what caused it, not just assume
it was a permissions error.
except IOError:
print("This file doesn't exist")
That's not what IOError means either. That is why it isn't called
FileDoesntExistError. Again, you need to look at the exception to see
what the error actually is.
In particular, you should always _either_ inspect the exception to see what
went wrong and handle it, _or_ include the exception text in your error
message, for example:
except IOError as e:
print("IO Error on file:", e)
That way an unhandled exception gets reported.
else:
os.rename(new_filename, filename + 'txt')
os.rename(new_filename, path)
Importantly:
os.rename(path, new_filename)
The old name comes first, then the new name.
Also, you might want to ensure that new_filename doesn't already exist...
Cheers,
Cameron Simpson <c...@cskk.id.au>
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