MATLAB: How to pass many input arguments into a function at once

input argumentsisequal

Hi,

I'm using the isequal function to compare if certain table columns are equal.

I'm currently doing this by passing the name of the table columns in manually for each input argument like so:

correct_order = isequal(a.ID1,a.ID2,a.ID3,a.ID4, a.ID5);

However, as I'll have a different number of columns (e.g. a.ID1, a.ID2… a.IDn) each analysis, I want a way to pass all table columns that begin with 'ID' into the isequal argument at once.

Something along the lines of:

correct_order = isequal(a.ID*);

where * denotes a wildcard for all columns in table a that begin with 'ID'.

Thanks.

Best Answer

You can extract all columns of the for ID* using contains() as follow

requiredColumns = contains(TABLE.Properties.VariableNames, 'ID');
TABLEnew = TABLE{:, requiredColumns};
TABLEnew = num2cell(TABLEnew, 1);
isequal(TABLEnew{:})

Related Solutions

MATLAB: Is it possible to split a table into multiple tables based in ID (a number code) in colum A

Yes, definitely.

filename = 'AppropriateFileName.csv'
T = readtable(filename);
G = findgroups(T{:,1});     %first column
Tc = splitapply( @(varargin) varargin, T, G);

Now Tc is a cell array of table objects, one cell entry for each unique identifier from the first column.

I use a bit of a hack here to do the cell array conversion. When you call a function with arguments, and the function uses the special parameter name varargin, then within the function you can refer to the entire set of arguments from that position onwards, as the cell array varargin, with the first entry being the first parameter there, the second being the second parameter there, and so on. within the @(varargin) anonymous function, whatever was passed in as potentially multiple arguments can be referred to as the cell varargin. And what I return from the function is varargin -- which is to say the cell array of arguments. The effect is the same as

@(var1, var2, var3, ... varN) {var1, var2, var3, ..., varN}

but you do not need to worry about how many arguments there were.

The net result is to wrap each of the partitioned table sections into a cell.

MATLAB: Indexing a cell array in a table

When you try to access contents of multiple cells, MATLAB creates a comma-separated list. Because each cell can contain a different type of data, you cannot assign this list to a single variable. However, you can assign the list to the same number of variables as cells. MATLAB assigns to the variables in column order.

Check the following link for more information:

http://www.mathworks.com/help/releases/R2014a/matlab/matlab_prog/access-data-in-a-cell-array.html

Modifying the code as

myCell = {'a';'b';'c';'d';'e'};
myTable = table(myCell)
isequal(myCell{1},vertcat(myTable.myCell)) 
isequal(vertcat(myCell),vertcat(myTable.myCell))

seems to work.

Best Answer

Related Solutions

MATLAB: Is it possible to split a table into multiple tables based in ID (a number code) in colum A

MATLAB: Indexing a cell array in a table

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