Marko Rauhamaa wrote:
Chris Angelico <ros...@gmail.com>:
3) Every invocation of method() has to execute the class body, which
takes time.
That's what happens with every method invocation in Python regardless.
No, it doesn't! Invoking a method involves creating a bound method
object, which is very small and lightweight. Executing a class
statement creates a class object, which is enormous by comparison,
and quite expensive to initialise.
A quick test of your Outer class vs. Chris Angelico's version
suggests that yours is about 12 times slower at creating instances
of Inner.
from timeit import timeit
class Outer1:
def method(self):
outer = self
class Inner:
def spam(self, a, b):
outer.quarantine(a, b)
return Inner()
def quarantine(self, a, b):
pass
def test1():
x = Outer1()
for i in range(100000):
y = x.method()
y.spam(1, 2)
class Outer2:
class Inner:
def __init__(self, outer):
self.outer = outer
def spam(self, a, b):
self.outer.quarantine(a, b)
def method(self):
return self.Inner(self)
def quarantine(self, a, b):
pass
def test2():
x = Outer2()
for i in range(100000):
y = x.method()
y.spam(1, 2)
t1 = timeit(test1, number = 1)
print("Nested class: ", t1)
t2 = timeit(test2, number = 1)
print("Non-nested class:", t2)
print("Ratio =", t1 / t2)
----------------------------------------------
Results:
----------------------------------------------
Nested class: 1.899524817999918
Non-nested class: 0.15806536600030086
Ratio = 12.01733729573816
--
Greg
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