Setdiff with two datasets, looking at only certain columns

I have two datasets, they have the same column headings and different number of rows. I want to create a new dataset that pulls out what they have in common (intersect) and also what is unique in one versus the other (setdiff).

I would use what I have written above, except that I want to focus in on two columns and pull out the entire row of data.

*Dataset 1:*

Name Position Letter

1 587 A

1 848 A

5 398 B

*Dataset 2:*

Name Position Letter

1 587 B

1 848 C

2 3188 B

8 3282 G

I want to generate a new dataset that looks only at the first and second column to generate new datasets.

For example I want to generate the following if I am looking for "unique" rows present in dataset 1, but not dataset 2:

Dataset 3:

Name Position Letter

5 398 B

Whereas I would generate the following if I am looking for common rows present in dataset 1 that are also in dataset 2:

Dataset 4

Name Position Letter

1 587 A  
1 848 A

Even suggestions for commands to look at would be appreciated. Thanks in advance.

Answer 1

[Ramnarayan Krishnamurthy]

You can use the ' setdiff' and ' intersect' functions with logical indexing to get the output you desire.

As an example:

% Set up the tables
T = table([1;1;5],[587;848;398],{'A';'A';'B'},'VariableNames',{'Name','Position','Letter'})

T2 = table([1;1;2;8],[587;848;3188;3282],{'B';'C';'B';'G'},'VariableNames',{'Name','Position','Letter'})

% The second output argument is the index (Row) in Table T 
% We are "looking" at the first 2 columns only
[~,index1] = setdiff(T(:,1:2),T2(:,1:2))

% Displaying only the appropriate entry
T(index1,:)

% Same syntax as setdiff
[~,index2] = intersect(T(:,1:2),T2(:,1:2))

% Displaying only the appropriate entry
T(index2,:)

HTH