Actually I do not see a reply from Peter?????? I don't have a clue what
was said.
I realize that performance is not a big issue in this case - of course
an increase in speed is always welcome. I was more interested in a
better understanding of the list comprehensions. Since I have so many
of these loops I thought it might be best if I tried using comprehensions.
Johnf
On 6/24/19 10:48 AM, Mats Wichmann wrote:
On 6/24/19 10:15 AM, johnf wrote:
.
Since I use a lot of similar loops to populate many dropdown controls I
started investigating the use of list comprehensions. But I can't
figure out how to use them in this loop and wonder if it will improve
the performance.
To amplify a tiny bit on what Peter said: comprehensions are a more
concise way to express a loop-to-build-a-collection, but I don't believe
were intended specifically as a performance improvement.
They may be a little faster on the principle of "avoiding dots" - that
is, the lookup every time through your loop from listname.append does
take a little bit of time. And probably more significantly, append is a
function that has to be called, and the setup stack frame/call/return
sequence also takes some time. So depending on circumstances you may see
insignificant or significant performance differences.
But, again -
Rule number one: only optimize when there is a proven speed bottleneck
_______________________________________________
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
https://mail.python.org/mailman/listinfo/tutor
_______________________________________________
Tutor maillist - Tutor@python.org
To unsubscribe or change subscription options:
https://mail.python.org/mailman/listinfo/tutor
