Question

For the example below:

 if a == 100:
     # Five lines of code
 elif a == 200:
     # Five lines of code

Five lines of code is common and repeating how can I avoid it?
I know about putting it a function

or

if a == 100 or a == 200:
    # Five lines of code
    if a == 100:
        # Do something
    elif a == 200:
        # Do something

Any other cleaner solution?

Answer 1

Remember that with functions, you can have local functions with a closure. This means you can avoid passing repetitive arguments and still modify locals. (Just be careful with assignments in that local function. Also see the nonlocal keyword in Python 3.)

def some_func(a):
  L = []

  def append():
    L.append(a)  # for the sake of example
    #...

  if a == 100:
    append()
    #...
  elif a == 200:
    append()
    #...