MATLAB: Join tables based on string in one cell in the other

table cell string

I have 2 tables, call them foo and bar. foo has strings in the form "foobar" in column 1. bar has strings in the form 'foobar' in column one.

foo{1,1} = "060514191658"
bar{1,1} =  1×1 cell array    {'060514191658'}
foo(1,1) =  table        CaseID        "060514191658"
bar(1,1) =  table        CaseID       '060514191658'

When I try

>> join(foo,bar)

I get:

Error using tabular/join (line 129)
Left and right key variables 'CaseID' and 'CaseID' are not comparable because one is a non-cell.

How do I convert one or another to be able to join on this column.

I've tried every conversion I can think of and still can't get there.

Best Answer

You need to convert strings in foo.var1 to characters, assuming the 1st column name in foo and bar are both 'var1'.

Run:

foo.var1_converted = cellfun(@(x) char(x),foo.var1,'UniformOutput',false);

then you will get a new column 'var1_converted' in foo, which contains the converted characters from strings in column 'var1'.

Then run:

new_tab = join(foo,bar,'leftkeys','var1_converted','rightkeys','var1');

you will get your joined table.

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% Create fake data
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More info on characters vs. strings:

https://www.mathworks.com/help/matlab/characters-and-strings.html

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There are many useful functions to know when working with structures in MATLAB. First is the function fieldnames which will return a cell array of all the names of all the fields in the structure e.g.

given a structure:

foo.bar_1 = 6;
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foo.bar_3 = [1,2,3];

the command:

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{'bar_1'; 'bar_2'; 'bar_3'}

Once you have the field names in a cell array you can access the data in the structure in a loop e.g.

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Actually sending this data to an excel sheet will depend greatly on the format of your data and how you want to store it in the spreadsheet. To do this you should use the function xlswrite.

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