A function name can become a variable name (and thus be passed as an argument) by dropping the parentheses. A variable name can become a function name by adding the parentheses. In your example, equate the variable rules to one of your functions, leaving off the parentheses and the mention of the argument.
Functions can be passed into other functions Functions, like any other object, can be passed as an argument to another function.
To pass a function as an argument to another function, write the name of the function without parenthesis in the function call statement (just like what we do with variables) and accept the reference of the function as a parameter in the called function.
In Python, any written function can be called by another function. Note that this could be the most elegant way of breaking a problem into chunks of small problems.
Just pass it in like any other parameter:
def a(x):
return "a(%s)" % (x,)
def b(f,x):
return f(x)
print b(a,10)
Treat function as variable in your program so you can just pass them to other functions easily:
def test ():
print "test was invoked"
def invoker(func):
func()
invoker(test) # prints test was invoked
For passing both a function, and any arguments to the function:
from typing import Callable
def looper(fn: Callable, n:int, *args, **kwargs):
"""
Call a function `n` times
Parameters
----------
fn: Callable
Function to be called.
n: int
Number of times to call `func`.
*args
Positional arguments to be passed to `func`.
**kwargs
Keyword arguments to be passed to `func`.
Example
-------
>>> def foo(a:Union[float, int], b:Union[float, int]):
... '''The function to pass'''
... print(a+b)
>>> looper(foo, 3, 2, b=4)
6
6
6
"""
for i in range(n):
fn(*args, **kwargs)
Depending on what you are doing, it could make sense to define a decorator
, or perhaps use functools.partial
.
Just pass it in, like this:
Game(list_a, list_b, Rule1)
and then your Game function could look something like this (still pseudocode):
def Game(listA, listB, rules=None):
if rules:
# do something useful
# ...
result = rules(variable) # this is how you can call your rule
else:
# do something useful without rules
A function name can become a variable name (and thus be passed as an argument) by dropping the parentheses. A variable name can become a function name by adding the parentheses.
In your example, equate the variable rules
to one of your functions, leaving off the parentheses and the mention of the argument. Then in your game()
function, invoke rules( v )
with the parentheses and the v
parameter.
if puzzle == type1:
rules = Rule1
else:
rules = Rule2
def Game(listA, listB, rules):
if rules( v ) == True:
do...
else:
do...
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