Steven D'Aprano wrote:
On Tue, 02 Sep 2008 18:56:48 -0500, Robert Kern wrote:
ssecorp wrote:
or why does this take so god damn long time?
Several reasons. One of which is that try: except: is slow.
I beg to differ. Setting up a try...except block is very fast. Here's an
example in Python 2.5:
from timeit import Timer
Timer('len("abc")').repeat()
[0.27346706390380859, 0.1530919075012207, 0.14886784553527832]
Timer('''try:
... len("abc")
... except:
... pass
... ''').repeat()
[0.27847194671630859, 0.19191384315490723, 0.19077491760253906]
The difference (approx 0.04 microseconds) applicable to setting up the
try...except block is trivial, of the same magnitude as a pass statement:
Timer('pass').repeat()
[0.059719085693359375, 0.060056924819946289, 0.059512138366699219]
However, *catching* the exception may be relatively slow:
Timer('''try:
... len(abc) # raise a NameError
... except:
... pass
... ''').repeat()
[3.2067418098449707, 2.7088210582733154, 1.9558219909667969]
You're right. My mistake. I was misremembering Guido's old essay about try:
except: versus if: else:.
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco
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