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copied!<p>I think the problem is that you need to know the arity of each function, in order to assign the arguments of the "combined" function accordingly.</p> <p>Maybe you can wrap your functions in a class, something like this:</p> <pre><code>class Function: def __init__ (self, arity, f): self.arity = arity self.f = f def __call__ (self, *args): return self.f (*args) def __add__ (self, g): if not isinstance (g, Function): raise Exception ('Here be dragons') def fg (*args): return self.f (*args [:self.arity] ) + g.f (*args [self.arity:] ) return Function (self.arity + g.arity, fg) a = Function (4, lambda x1, x2, x3, x4: (x1 * x2) + (x3 * x4) ) b = Function (2, lambda x1, x2: x1 / x2) print (a (1, 2, 3, 4) ) print (b (10, 20) ) c = a + b print (c (1, 2, 3, 4, 10, 20) ) </code></pre> <hr> <p>Some words on inspection of the arity. The resulting function <code>fg</code> has only one argument, namely <code>*x</code> and its inspected arity will result in 0, hence prohibiting adding already added functions. Take a look here:</p> <pre><code>#Using my original class a = Function (2, lambda x1, x2: x1 * x2) b = Function (2, lambda x1, x2: x1 / x2) c = a + a print (c (1, 2, 3, 4) ) #prints 14 c = c + b print (c (1, 2, 3, 4, 5, 6) ) #prints 14.833333333333334 </code></pre> <p>Now if we use inspection like this (please correct me if you intended another use of it):</p> <pre><code>import inspect class InspectedFunction: def __init__ (self, f): self.f = f def __call__ (self, *args): return self.f (*args) def __add__ (self, g): if not isinstance (g, InspectedFunction): raise Exception ('Here be dragons') arity = len (inspect.getargspec (self.f).args) def fg (*args): return self.f (*args [:arity] ) + g.f (*args [arity:] ) return InspectedFunction (fg) a = InspectedFunction (lambda x1, x2: x1 * x2) b = InspectedFunction (lambda x1, x2: x1 / x2) c = a + a print (c (1, 2, 3, 4) ) #prints 14 c = c + b print (c (1, 2, 3, 4, 5, 6) ) #inspected arity of c is 0 </code></pre> <p>will do this:</p> <pre><code>Traceback (most recent call last): File "nomimporta.py", line 45, in <module> print (c (1, 2, 3, 4, 5, 6) ) File "nomimporta.py", line 30, in __call__ return self.f (*args) File "nomimporta.py", line 37, in fg return self.f (*args [:arity] ) + g.f (*args [arity:] ) File "nomimporta.py", line 37, in fg return self.f (*args [:arity] ) + g.f (*args [arity:] ) TypeError: <lambda>() takes exactly 2 arguments (0 given) </code></pre>

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