Specifying "MergeKeys" for "innerjoin"

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FM 2022-11-9

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https://ww2.mathworks.cn/matlabcentral/answers/1847303-specifying-mergekeys-for-innerjoin

评论： FM 2022-11-18

I wonder what people feel about incorporating a MergeKeys option into "innerjoin", similar to what is available for "outerjoin"?

The "innerjoin" function merges keys by default, but doesn't do so when specifying "LeftVariables" and "RightVariables". I want to use those options because my left and right tables have a lot of variables, and I only want a small subset to show up in the inner join. Hence, I have to write extra code that merges the keys, in effect, but anything I can do to keep the code volume down will reduce the cognitive noise.

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Answer 1

Lei Hou 2022-11-18

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https://ww2.mathworks.cn/matlabcentral/answers/1847303-specifying-mergekeys-for-innerjoin#answer_1104413

Hi,

Regarding the output of innerjoin, the key values from left table are the same as that from the right table. So, we only need to keep one copy. You can add key variable names to either "LeftVaribles" or "RightVariables" but not both.

Hoping this is helpful.

Thanks,

Lei