error using the join function

FinalData = join(All,M4,'Keys','ID','Year');

% I want to join All and M4 based on the common variables ID and Year. I want all columns of All and the additional columns of B when there is a match based on ID and Year. I am receiving an error :

Error using tabular/join Wrong number of arguments.

What went wrong?

Answer 1

[Stephen23]

"What went wrong?"

You need to provide multiple key names as one input argument, not as two separate input arguments. This means simply providing the key names as character vectors in a cell array:

FinalData = join(All,M4,'Keys',{'ID','Year'});
%                              ^           ^

This is explained in the JOIN documentation:

https://www.mathworks.com/help/matlab/ref/table.join.html#d124e1558433

Answer 2

[Dyuman Joshi]

The corrext syntax is -

FinalData = join(All,M4,'Keys',{'ID','Year'}); 
%or
FinalData = join(All,M4,'Keys',["ID","Year"]);

Refer to the documentation page of join for more information.

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