Steven D'Aprano a écrit : > On Sun, 19 Nov 2006 13:18:39 +0100, Bjoern Schliessmann wrote: > > >>Imbaud Pierre wrote: >> >> >>> tf = tempfile.NamedTemporaryFile() >>> tfName = tf.name >>>[...] >>> print >> sys.stderr, '%s: %s' % (tfName, ['no', >>>'yes'][os.path.exists(tfName)]) >>> subprocess.Popen(['strings', tfName]) >> >>Just out of curiosity: Why did you assign tf.name to tfname? >> >>Hypothetically, if tf.name changed, tfname wouldn't follow since >>strings are immutable. > > > Well, yes, but if tf.name changed, that won't change the file name on disk > either: > > >>>>tf = tempfile.NamedTemporaryFile() >>>>tf.name > > '/tmp/tmpYVV1Ij' > >>>>os.path.exists(tf.name) > > True > >>>>oldname = tf.name >>>>tf.name = "/tmp/something" >>>>os.path.exists(tf.name) > > False > >>>>os.path.exists(oldname) > > True > > > I'm guessing that binding tf.name to tfName is a micro-optimization. indeed. And I dont see why tf.name would change. In a > very tight loop, name lookups can take considerable time, and one > optimization can be to reduce the number of lookups: > > method = something.method > while 1: > something.method # needs at least two lookups > method # needs a single lookup > >
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