Containers.Map how to set keys and values

Hello, so I want to create a Containers.Map. However, I am unsure of how to create it as the data that I want to use as key values is embedded in a cell array. For example, the cell array is 15x1 and looks like this: [1501x15 table, 1501x15 table....etc]I want to create a containers map that uses the 6th column of EACH table as the key values and the 8th column as the pairing values. How do I go about doing this?

Answer 1

[Sudhanshu Bhatt]

Hi Xander,

I am assuming that you already have a cell array which contains tables as cells.

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: T1; T2

Step 1: Fetch a Table from the cell array :

>> grabATable = tableAsCells{1};

Step 2: Fetch columns from the table that you want to keep as keys:

>> keySets = table2cell(grabATable(:,5));

The function "table2cell" will convert the 5th column of the table elements into a cell array , which will act as our keys in the container.Map object.

Step 3: Fetch column from the table to be the values:

>> valueSets = table2cell(grabATable(:,3));

The function "table2array" will convert the 5th column of the table elements into a cell , which will act as our values in the container.Map object. NOTE: We could also use "table2array" function here.

Step 4: Put the keySets and valueSets in a container.Map object:

>> mapObj = containers.Map(keySets,valueSets);

Step 5: Fetching values form the map.

>> mapObj('Any_Key_From_keySets_cell_array');

For Example:

>> mapObj('Williams');

More information on "table2cell" , "table2array" and "containers.Map" can be found in the documentation links below:

table2cell Function MATLAB

table2array Function MATLAB

container.Map class MATLAB

Note: If you have to append in the map, if can be only done column wise.

I have attached a sample code to try this.

Hope this helps.

Thanks

Sudhanshu Bhatt

[xander fong]

Thanks! Do you mind taking a look at the other question I posted? link: http://www.mathworks.com/matlabcentral/answers/231059-creating-new-column-using-containers-map-skip-to-next-row-if-key-doesn-t-exist