Python中如何避免方法调用重复传参？验证新手解法

Great question, and your solution is totally correct—this is exactly the right way to handle repeated keyword arguments in Python!

Your approach uses dictionary unpacking with the ** operator, which takes the key-value pairs from your merge_args dict and passes them as individual keyword arguments to the merge() method. So when you write:

self.comp_train_df.merge(..., **merge_args)

It’s equivalent to writing:

self.comp_train_df.merge(..., left_index=True, right_index=True)

But with the huge benefit that if you ever need to change those parameters (like adding how='left' later), you only have to update the merge_args dict once instead of every single merge() call. This follows the DRY (Don’t Repeat Yourself) principle, making your code cleaner and far easier to maintain.

This is a common, idiomatic pattern in Python whenever you find yourself repeating the same keyword arguments across multiple function or method calls. If you wanted to take it a step further (especially if you’re doing more than just merging with those arguments), you could even create a small helper function to wrap the merge logic:

def merge_with_index(df, other_df):
    return df.merge(other_df, left_index=True, right_index=True)

# Then use it like this:
for col in self.numerical_columns:
    self.comp_train_df = merge_with_index(self.comp_train_df, self.get_aggregates(self.train_df, col))
    self.comp_test_df = merge_with_index(self.comp_test_df, self.get_aggregates(self.test_df, col))

But your original dictionary unpacking approach is already perfect for this specific scenario—it’s concise, straightforward, and gets the job done without overcomplicating things.

Keep up the good work thinking about code reuse as a beginner—that’s a fantastic habit to build early!

内容的提问来源于stack exchange，提问作者gil.fernandes