Ian Clark wrote: > Stef Mientki wrote: >> hello, >> >> I discovered that boolean evaluation in Python is done "fast" >> (as soon as the condition is ok, the rest of the expression is ignored). >> >> Is this standard behavior or is there a compiler switch to turn it >> on/off ? > > It's called short circuit evaluation and as far as I know it's standard > in most all languages. This only occurs if a conditional evaluates to > True and the only other operators that still need to be evaluated are > 'or's or the condition evaluates to False and all the other operators > are 'and's. The reason is those other operators will never change the > outcome: True or'd with any number of False's will still be True and > False and'ed to any number of Trues will still be False. > > My question would be why would you *not* want this?
Pascal, and apparently Fortran, do not use short-circuit evaluation. I remember learning this gotcha in my seventh-grade Pascal class (plus I just googled it to make sure my memory was correct!). Frank -- http://mail.python.org/mailman/listinfo/python-list
