MATLAB: Using a containers.Map to find values

Question

Hello, so I have a 35×1 cell array that contains a table of data for every day. The cell array looks like "[1501×6 table, 1501×6 table….ETC]". In addition, I also have a containers.map based off of a 12000×2 excel pull in. My objective is to insert a 7th column in every table (or cell of the cell array), in which every cell of the table corresponds to the value assigned in the map (using the 4th column as the keys). How do I do this? I've used a for loop to no avail. My idea for code was:

For I:numel(data) data{I}=[data(:,6) values{i}(map,{data(:,4)}] end

Answer 1

Hi Xander,

I am assuming that you have the data you want to insert into the table as 7th column.

For this example we will consider the following structure:

TableName T1 ; Columns: Age,Height,Weight,BloodPressure,LastName

TableName T2 ; Columns: Age,Height,Weight,BloodPressure,LastName

CellArray tableAsCells; Rows: (Table T1); (Table T2)

NewColumn Smoker: {'Yes';'Yes';'Yes';'No';'No'};

There are two approaches to adding a column to an existing table as listed below:

Approach 1: Appending the new column to the pre-existing table:

Step 1: Fetch a Table from the cell array :

>> grabATable = tableAsCells{1};

Step 2: Add column to this table :

>> T1 = [T1, Smoker];
>> T1.Properties.VariableNames(6) = {'Smoker'};

Approach 2: Creating a temporary table and concatenating it to the original table :

Step 1: Fetch a Table from the cell array :

>> grabATable = tableAsCells{1};

Step 2: Add column to this table :

>> newTable = table(Smoker);
>> T1 = [T1,newTable];

Below are the steps to add key and value objects to the Existing container.Map object:

Step 1: Creating new key and Value pairs :

>> newKeyValueSets = {'PlaceHolder1', 'PlaceHolder2', 'PlaceHodler3', 'PlaceHoler4' };
>> newValueSets = {100,110,120,130};

Step 2: Creating a new Map object :

>> newMapObj = containers.Map(newKeyValueSets,newValueSets);

Step 3: Concatenate the two map objects into the original object :

>> mapObj = [mapObj; newMapObj];

More information on concatenating values to map objects can be found in the documentation link below:

Concatenating into container.Map Objects

Hope this helps.

Thanks

Sudhanshu Bhatt