如何在python中重复/扩展表达式

Question

What is the most pythonic way to repeat an expression in Python.

Context : A function is getting passed a dictionary (with possibly 20 elements) and I need to extract and use values from this dictionary if they exist . Something like this :

x = dict_name['key1'] if dict_name['key1'] else ''

Now, instead of writing this logic 20 times for all 20 different keys, I would like to define this expression at one place and then use it repeatedly. It will be easier to maintain in future. In "C/C++" programming languages, it makes a good case of #define or inline functions. What would be Pythonic way to do this in Python?

As you would have guessed, I am novice in Python. So I appreciate your help on this or pointers to constructs for this in Python.

Answer 1

Whether there is an "equivalent" to inline in Python depends on who you ask, and what you check.

For no equivalent, eg: https://stackoverflow.com/a/6442497/2707864

For equivalent, eg: https://www.safaribooksonline.com/library/view/python-cookbook-3rd/9781449357337/ch07s06.html

From a practical point of view, lambda would do the trick ( dict.get replaces your ternary conditional operator)

dict_get = lambda key : dict_name.get(key, '')

Or you can always define a one-line function.

def dict_get( key ) : dict_name.get( key, '' )

Pythonicity is quite often (always?) subjective.