MATLAB: Join or Merge Data

datasetjoin;MATLABmergestrcmp

Hi, I have two large cells that I need to effectively "JOIN" together via two fields (one text and one numeric). Say one cell has 3 fields ID1(text),Date1(numeric),DataElement1(numeric). Say the second cell has 3 fields ID2, Date2, DataElement2. I need to have a third cell with a left outer join from cell1->cell2 on Id1->Id2 and Date1->Date2. This effectively will return me cell number one with an additional column (DataElement2).

What is the most effective way to go about doing this? Would it be turning the cell's into data-sets and performing the join function? I can easily write a loop to go one security at a time but because of the nature of text search functions (strcmp) this is incredibly slow when I have a million records or so to perform the search on.

Any suggestions would be much appreciated – thanks! Brian

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These FEX contributions might help

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MATLAB: Do I obtain an error about string cells when I try to join two datasets in MATLAB (R2013a)

The reason behind the error is that the content of your dataset, under the variable name 'key1' must be of type 'char", and not "double", as in your case.

To circumvent this issue, you need to do a data-type conversion. Here is an example that illustrates that. Say, your variable name tagged "key1" is located in column "idx1" in "dataset1" and in column "idx2" in "dataset2".

>> varName1 = dataset1.Properties.VarNames(idx1);
>> cellData1  = dataset2cell(dataset1(:,idx1));
>> data1    = cellData1(2:end,2);
>> data1    = cellfun(@num2str,data1,'UniformOutput',false);
>> ds1      = dataset(data1,'Varnames',varName1,'ObsNames',dataset1.Properties.ObsNames);
>> dataset1(:,idx1) = ds1;
>> varName2 = StatSet.Properties.VarNames(idx2);
>> cellData2  = dataset2cell(dataset2(:,idx2));
>> data2    = cellData2(2:end,2);
>> data2    = cellfun(@num2str,data2,'UniformOutput',false);
>> ds2      = dataset(data2,'Varnames',varName2,'ObsNames',dataset2.Properties.ObsNames);
dataset2(:,idx2) = ds2;
C = join(dataset1,dataset2,'Key','key1');

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MATLAB: Loop Through a Cell Array

MATLAB: Do I obtain an error about string cells when I try to join two datasets in MATLAB (R2013a)

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