Let's say you don't want to just return a value, but want to use methods that change something on an object. Using the approach stated here would be:

result = {
  'a': obj.increment(x),
  'b': obj.decrement(x)
}.get(value, obj.default(x))

What happens here is that python evaluates all methods in the dictionary. So even if your value is 'a', the object will get incremented and decremented by x.

Solution:

func, args = {
  'a' : (obj.increment, (x,)),
  'b' : (obj.decrement, (x,)),
}.get(value, (obj.default, (x,)))

result = func(*args)

So you get a list containing a function and its arguments. This way, only the function pointer and the argument list get returned, not evaluated. 'result' then evaluates the returned function call.

Let's say you don't want to just return a value, but want to use methods that change something on an object. Using the approach stated here would be:

result = {
  'a': obj.increment(x),
  'b': obj.decrement(x)
}.get(value, obj.default(x))

Here Python evaluates all methods in the dictionary.

So even if your value is 'a', the object will get incremented and decremented by x.

Solution:

func, args = {
  'a' : (obj.increment, (x,)),
  'b' : (obj.decrement, (x,)),
}.get(value, (obj.default, (x,)))

result = func(*args)

So you get a list containing a function and its arguments. This way, only the function pointer and the argument list get returned, not evaluated. 'result' then evaluates the returned function call.