Error Attempt to execute SCRIPT join_function as a function:

I'm trying to merge 100 tables from a cell array. I'm trying to use loop that calls the function 'join_function' but I get this error. Can anyone help?

join_function:

c = outerjoin(data{1,1},data{1,2},'Keys','time','MergeKeys',true);

loop:

numfiles = 100;
demand = table(1, numfiles);

for j = 1:numfiles
    demand_file = sprintf('data{1,%d}', j);
    demand{k} = join_function(demand_file);
end

error message from commanf window:

Attempt to execute SCRIPT join_function as a function:
C:\Users\Mark\Downloads\join_function.m

Error in testjoinall (line 14)
    demand{k} = join_function(demand_file);

Answer 1

[Jan]

The error message is clear: join_function.m is a script file and then it does not accept input arguments. Only functions do this. See https://www.mathworks.com/help/matlab/matlab_prog/scripts-and-functions.html and https://www.mathworks.com/help/matlab/learn_matlab/scripts-and-functions.html .

The code has more problems. sprintf('data{1,%d}', j) creates strings, char vectors to be exact. But in the joining you try to access the contents of an data array. This is something completely different. 'data{1,2}' is a char vector, but does not carry any information about the array called "data".

It is strange, that you create 'data{1,1}' in the loop, but try to access the two elements of the cell array data{1,1} and data{1,2} inside the outerjoin function.

I guess, you want something like this:

numfiles = 100;
demand   = table();
for j = 1:numfiles
  demand = outerjoin(demand, data{1, j}, 'Keys', 'time', 'MergeKeys', true);
end

[Mark Rodger]

Thanks, I've tried this but I get an error saying "unrecognized varaible name 'time'." Do you know how to over come this?

[Walter Roberson]

outerjoin is a function that applies to table objects and timetable objects. When you specify 'Keys', 'time', that tells MATLAB that it should look inside the table for a column named 'time' and use that column to do the join. The message you are getting is because your table does not contain 'time'

[Mark Rodger]

But all the tables have 'time'.

[Walter Roberson]

Jan's suggested code

demand = table()

created a table with no variables. You would need to omit that line

[Jan]

You can omit the initialization with an empty table, but use the first table and start the concatenation at the 2nd one:

numfiles = 100;
demand   = data{1, 1};
for j = 2:numfiles
  demand = outerjoin(demand, data{1, j}, 'Keys', 'time', 'MergeKeys', true);
end