On 3/25/2015 3:50 PM, Ivan Evstegneev wrote:
Googled a bit, and found only one, a "ValueError" exception, but still don't
understand how it should be implemented in my case.
Should my code look like this one:
def my_fun(history=False, built=False, current=False, topo=None,
full=False, file=None):
try:
if currnet and full:
do something_1
elif current and file:
do something_2
elif history and full and file:
do something_3
except ValueError:
print("No valid input! Please try again ...")
You need to raise ValueError, not try to catch one that never occurs.
def my_fun(history=False, built=False, current=False, topo=None,
full=False, file=None):
if current and full:
do something_1
elif current and file:
do something_2
elif history and full and file:
do something_3
else:
raise ValueError("not a valid combination of arguments")
My answer does not negate the possibility that Ian is correct that you
are trying to do too much in one function. But I did want to point out
that there are stdlib precedents for excluding invalid argument
combinations. However, in those cases, only a small proportion of
combinations are invalid and if the function were split, most of the
code would be duplicated.
Here is an mutually exclusive combo that is *not* flagged: passing both
'-' (read from stdin) and 'file.py' to python on the command line. The
first wins and the second is ignored. '-i -' is redundant and ignored.
--
Terry Jan Reedy
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