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Date: Tue, 26 May 2015 18:18:04 -0700
From: Gary Herron <gary.herron@islandtraining.com>
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Subject: Re: Array of Functions
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On 05/26/2015 05:43 PM, richard_riehle wrote:
> I realized that I mentioned earlier that I found a solution to my original question, but that I never posted an example of the solution.   So, here is a simplified example for anyone who is interested.
>
> def fArray(fselect, fparm  = 1):
> 	def A1(p = fparm):
> 		if p == 1:
> 			print("printing A1[1]")
> 		else:
> 			print("printing A1[other]")
> 	def A2(p = fparm):
> 		if p == 1:
> 			print("printing A2[1]")
> 		else:
> 			print("printing A2[other]")
> 	A = [A1, A2]
> 	A[fselect]()

Nested functions are often confusing and unclear, and there is really no 
need for them here.   This does the same thing:


def A1(p):
     print("printing",  "A1[1]" if p==1 else "A1[other]"))

def A2(p):
     print("printing",  "A2[1]" if p==1 else "A2[other]"))

def fArray(fselect, fparm=1):
     A = [A1,A2]
     A[fselect](fparm)


> In this example, I enclosed two functions within another function, and then put those two functions in a list.  Then, with appropriate parameters, I called one of the functions in the list, associated the formal parameter with the function in a call to the array, and presto, it performs the function.
>
> The more advanced problem I wanted to solve, a two dimensional array of functions, once this example is understood, becomes trivial to implement.  In fact, the more interesting problem I wanted to solve involved a dictionary of functions in a two-dimensional array, and that too was easy to do in Python.
>
> When I compare what this would require in C, C++, Java, or most other languages, I find Python to be really easy for solving this kind of problem.
>
> Next, I plan to develop the solution using decorators and assertions to empower it with a greater level of portability and to make the functions more generic.
>
> I hope someone finds this interesting.
>
> Richard Riehle, PhD
>
>