How to retrieve tables from a cell array

assuming we have some data files and we are storing the data of these files in a cell array called "results", the cell array contains two columns the first is for the name of the file and the second one we have each cell contains multiple tables corresponding to a data file. (see the images below).

Now, assuming that each table of these has a unique "Date" value for the data in it, How can we go through all the cells in the cell array for all the files we have to retrieve the tables that there "Date" value is between for example (196611110928 and 196611110940) or any other values?

I was able to sort this out for having a specific value of the Date, i.e for retrieving a single table, but when having a certain range of the Date values and retrieving multiple tables I am not sure how to do that.. anyone can help?

Answer 1

[Shanmukha Voggu]

Hi Osama,

I understood that you want to know

1)how to loop over all cells in the cell array(results)

2)how to loop over all the tables in the cell

According to question I understood that if every row of table has the Date in the specific range for example (196611110928 and 196611110940), then that table can be retrieved

The finalCell is the cell array that contains all the resultant tables

finalCell={};% contains all tables having Date range (196611110928 ,196611110940)
for i=1:size(results,2)% "results" is the cell array mentioned in question
    currCell=results{i,2};% current cell in the iteration
    for j=1:size(currCell,1)
        currTable=currCell{j,1};% current table in the iteration
        booleanMatrix=(boolean(ones(size(currTable,1))))';% creating a Boolean matrix that contains all logical 1's
        if((currTable.Date>196611110928 & currTable.Date<196611110940)==booleanMatrix)% This condition will true when the Date is in given range
            finalCell{end+1}=currTable;% if above condition is true, then add the table to cell array
        end
    end
end

Note: Before executing following code make sure to have results variable in the workspace.

Refer this for more information.

[MA]

thank you for replying to my question, you understood my question correctly. But when runing your code I am getting this error for some reason :

Unrecognized function or variable 'boolean'.

Error in extractingtables (line 48)
        booleanMatrix=(boolean(ones(size(currTable,1))))';% creating a Boolean matrix that contains all logical 1's

[Shanmukha Voggu]

A quick fix can be using the following code without using the boolean keyword, which gives the same result as the previous code

finalCell={};% contains all tables having Date range (196611110928 ,196611110940)
for i=1:size(results,2)% "results" is the cell array mentioned in question
    currCell=results{i,2};% current cell in the iteration
    for j=1:size(currCell,1)
        currTable=currCell{j,1};% current table in the iteration
        booleanMatrix=(ones(size(currTable,1)))';% boolean keyword is removed which was present in previous code
        if((currTable.Date>196611110928 & currTable.Date<196611110940)==booleanMatrix)% This condition will true when the Date is in given range
            finalCell{end+1}=currTable;% if above condition is true, then add the table to cell array
        end
    end
end

Refer this to know information about Unrecognized function or variable 'boolean'. error

[MA]

thank you very much it worked flawlessly.

[Stephen23]

currTable.Date>196611110928 & currTable.Date<196611110940)==booleanMatrix
%               This comparison is completely superfluous ^^

The LE and LT comparisons return TRUE/FALSE values, which the pointless EQ comparison compares against a vector of ONES to return exactly the same TRUE/FALSE values.

Do not learn from such pointlessly obfuscated code.

@Shanmukha Voggu: BOOLEAN is not a MATLAB function, LOGICAL is a MATLAB function. Rather then inventing functions that do not exist it is much more reliable to read the MATLAB documentation.

[Hailey Hayes]

I have a similar use case. I used this to help sort my tables and now I need to take a time difference within the sorted tables. The sorted tables are in their own cell array. Is there a way to perform subtraction on multiple tables within a cell array using a for loop?