for what are for/while else clauses
mwilson at the-wire.com
Thu Nov 20 03:14:27 CET 2003
In article <mailman.787.1069069214.702.python-list at python.org>,
"Fredrik Lundh" <fredrik at pythonware.com> wrote:
>for a while-statement, the controlling condition is the test at
>for a for loop, the condition is "is there another item" (to quote the
>language reference: "When the items are exhausted (which is imme-
>diately when the sequence is empty) ... the loop terminates.".
>for a try-except clause, the condition is "did the suite raise an
Interesting way to think about it. Thanks.
So in some sample code:
If the loop results in some_action being done, say, 17
times; then that means that some_condition was found true 17
times. The 18th time, some_condition is found to be false,
the else takes effect and last_action gets done one time.
The only wrinkle then is that the while loop construct
passes control to the following code after that one
last_action. But we expect that from a while loop.
The effect of a break in the suite controlled by the
while is to blow away execution of the whole while
construct, including the else.
As an explanation, I like it.
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