On 02/11/2015 08:27 AM, boB Stepp wrote:
Python 2.4.4, Solaris 10
I have a file of functions. Based on what is read in a data file,
different functions in the file of functions will need to be called. I
have been trying to make the following approach work, so far
unsuccessfully as, in general, each function may have a different
number of arguments that might have to be passed to it.
def func1(x1, x2, x3):
pass
def func2(y1, y2):
pass
def func3(z):
pass
call_fcn = {'a': func1, 'b': func2, 'c': func3}
call_fcn[key_letter](???)
How can I successfully pass the needed arguments needed for each
possible function with this approach? I naively tried to do something
like:
pass_args = {'a': (x1, x2, x3), 'b': (y1, y2), 'c': (z)}
call_fcn[key_letter](key_letter)
But ran into the syntax error that I was giving one argument when
(possibly) multiple arguments are expected.
Is what I am trying to do a viable approach that can be made to work?
Otherwise, I will brute-force my way through with if-elif-else
statements.
Thanks!
Sure, it's viable, but the best approach depends on your goal (use
case), and your restrictions. Are these functions really totally
unrelated to each other? You not only don't have the same number of
arguments, but the values don't even have anything in common?
There's an implied constraint that you're not permitted to change the
functions. Are you really constrained to only change the caller?
Assuming that you seriously want to be able to do this, the only use
case I can imagine are:
1) you're writing an interpreter
2) you're interfacing some network channel, where something at the
opposite end is sending you messages that you have to turn into local
function calls, and return results. A kind of RPC.
In each case, there are probably better ways. But you want this way, so
here goes: (code is untested)
pass_arg_dictionary = {'a': (x1, x2, x3), 'b': (y1, y2), 'c': (z)}
pass_args = pass_arg_dictionary[key_letter] #a list
call_fcn[key_letter]( *pass_args )
--
DaveA
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