python 2.7 - AttributeError: instance has no attribute 'function' -

class f: def f1(self, x):     return x def f2(self, x):     return 2.0*x def f3(self, x, function=f1):     return self.function(x) 

then

>>>f0=f() >>>f0.f3(1) 

the error is:

"attributeerror: f instance has no attribute 'function'" 

how can fix if still wanna f3() select function of f1 or f2 in class?

you can use .getattr():

class f:     def f1(self, x):         return x      def f2(self, x):         return 2.0 * x      def f3(self, x, function="f1"):         return getattr(self, function)(x) 

usage:

f0 = f() print(f0.f3(1))  # prints 1 print(f0.f3(1, "f2"))  # prints 2.0