question about file handling with "with"

Thu Mar 29 12:25:38 EDT 2012

On 2012年3月28日 11:31:21 +0200, Jabba Laci wrote:
> Is the following function correct? Is the input file closed in order?
>> def read_data_file(self):
> with open(self.data_file) as f:
> return json.loads(f.read())

Yes.
The whole point of being able to use a file as a context manager is so
that the file will be closed immediately upon leaving the with statement,
whether by falling off the end, "return", an exception, or whatever.
IOW, it's like calling .close() immediately after the "with" block, only
more so, i.e. it will also handle cases that an explicit .close() misses.