What is the best way to store a list of functions?

Question

I need to store a large numbers of functions rules in Python (around 100000 ), to be used after....

def rule1(x,y) :...
def rule2(x,y): ...

What is the best way to store, manage those function rules instance into Python structure ?

What about using Numpy dtype=np.object array ? (list are bad when they become too large...)

Main goal is to access in the fastest and minimum memory footprint when storing in memory.

Thanks

What exactly do you mean? do you mean storing the function names, storing the function calls, or storing the function instances? What is meant by _rules_? Do you mean storing function parameters? — Christian Dean, Aug 31 '16 at 21:40
Depends on where you want to store it. In a file? In memory? — Dmitry Torba, Aug 31 '16 at 21:42
You're going to have to be way more specific. As Mr.goosberry brought up, what exactly do you mean by "function rules?" Are these just function names, objects... what? And what exactly do you plan on doing? What will "managing" these "rules" involve? — juanpa.arrivillaga, Aug 31 '16 at 21:42

score 2 · Answer 1 · answered Aug 31 '16 at 21:42

2

Functions are first class objects in Python - you can store them just like you'd store any other variable or value:

def a():
  pass

def b():
  pass

funcs = [a,b]
funcs[0]() # calls `a()`.

answered Aug 31 '16 at 21:42

g.d.d.c

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aneroid · Answer 2 · 2016-08-31T21:50:46.040

1

When you use those rules, you're going to have to reference them somehow. If your example is a hint of the naming convention, then go with a list. Calling them in sequence would be easy via map or in a loop.

rules = [rule1, rule2, ...]
for fn in rules:
    fn(arg1, arg2)  # this calls rule1 and rule2 with args (as an example)

If you may also reference them by name, then use a dict, like:

rules = {'rule1': rule1, 'rule2': rule2, ...}
something = rules['rule5'](arg1, arg2)
# or
for rule in rules:  # iterates over the dict's keys
    rules[rule](arg1, arg2)

edited Aug 31 '16 at 21:50

answered Aug 31 '16 at 21:43

aneroid

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This was my original thinking as well; He wanted to store a list of function arguments. But it seems more likely that we wants to store a function instance. – Christian Dean Aug 31 '16 at 21:44
I'm not using it to store function arguments but the functions themselves. Using `some_args` just to show where arguments would go. – aneroid Aug 31 '16 at 21:47
Ok, I think i get what your doing now. – Christian Dean Aug 31 '16 at 21:49

What is the best way to store a list of functions?

2 Answers2