MATLAB: Trouble pivoting large table using unstack function

datastorepivotpivot tablestacktableunstack

I have a large table (6307840×42) that I need to pivot. To scale down the problem, let's assume the table looks something like this:
Measurement    Value     DUT #     DUT Barcode
___________    _____    _______    ___________
Temperature     50         1          ABC123 
Humidity        15         1          ABC123
Voltage         1.2        1          ABC123
Temperature     52         2          DEF456
Humidity        12         2          DEF456
Voltage         1.1        2          DEF456
Temperature     48         3          GHI789
Humidity        17         3          GHI789
Voltage         0.8        3          GHI789
I want to pivot the above table such that the values in the Measurement column become new column titles which contain the data stored in the Value column:
Temperature    Humidity    Voltage    DUT #    DUT Barcode
___________    ________    _______    _____    ___________
    50            15         1.2        1        ABC123
    52            12         1.1        2        DEF456
    48            17         0.8        3        GHI789
I have tried using the unstack function to achieve this, but the result spits out a 0x62 sized table containing only the pivoted variable names, but no data. My code looks something like this:
    ds = datastore('myTable.csv')
    myTable = readall(ds);
    myPivotedTable = unstack(myTable,'Value','Measurement');
Am I using the unstack function incorrectly? Am I approaching the problem compeltely the wrong way? Any help would be greatly appreciated.

Best Answer

Works fine for me with your little example:
Measurement = repmat({'Temperature'; 'Humidity'; 'Voltage'}, 3, 1);
Value = [50; 15; 1.2; 52; 12; 1.1; 48; 17; 0.8];
DUT = repelem([1; 2; 3], 3);
Barcode = repelem({'ABC123'; 'DEF456'; 'GHI789'}, 3);
myTable = table(Measurement, Value, DUT, Barcode)
unstack(myTable, 'Value', 'Measurement')
myTable =
  9×4 table
     Measurement     Value    DUT    Barcode 
    _____________    _____    ___    ________
    'Temperature'      50      1     'ABC123'
    'Humidity'         15      1     'ABC123'
    'Voltage'         1.2      1     'ABC123'
    'Temperature'      52      2     'DEF456'
    'Humidity'         12      2     'DEF456'
    'Voltage'         1.1      2     'DEF456'
    'Temperature'      48      3     'GHI789'
    'Humidity'         17      3     'GHI789'
    'Voltage'         0.8      3     'GHI789'
    
    
ans =
  3×5 table
    DUT    Barcode     Humidity    Temperature    Voltage
    ___    ________    ________    ___________    _______
     1     'ABC123'       15           50           1.2  
     2     'DEF456'       12           52           1.1  
     3     'GHI789'       17           48           0.8
so, I'm not sure why you end up with an empty result. However, not that if unique DUT don't match unique Barcode you're going to end up with a lot of NaN in your output (but it should never be empty). It may be better to consider either DUT or Barcode as a constant:
>> unstack(myTable, 'Value', 'Measurement', 'ConstantVariables', 'Barcode')
ans =
  3×5 table
    DUT    Barcode     Humidity    Temperature    Voltage
    ___    ________    ________    ___________    _______
     1     'ABC123'       15           50           1.2  
     2     'DEF456'       12           52           1.1  
     3     'GHI789'       17           48           0.8
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