MATLAB Programming Fundamentals - MathWorks

Read and Write Using Key Index

When reading from the Map, use the same keys that you have defined and associated with

particular values. Writing new entries to the Map requires that you supply the values to

store with a key for each one.

NoteFor a large Map, the keys and value methods use a lot of memory as their outputs

are cell arrays.

Read From Map

After you have constructed and populated your Map, you can begin to use it to store and

retrieve data. You use a Map in the same manner that you would an array, except that you

are not restricted to using integer indices. The general syntax for looking up a value

(valueN) for a given key (keyN) is shown here. If the key is a character vector, enclose it

in single quotation marks:

valueN = mapObj(keyN);

Start with the Map ticketMap :

ticketMap = containers.Map(...

{'2R175', 'B7398', 'A479GY', 'NZ1452'}, ...

{'James Enright', 'Carl Haynes', 'Sarah Latham', ...

'Bradley Reid'});

You can find any single value by indexing into the Map with the appropriate key:

passenger = ticketMap('2R175')

passenger =

James Enright

Find the person who holds ticket A479GY:

sprintf(' Would passenger %s please come to the desk?\n', ...

ticketMap('A479GY'))

ans =

Would passenger Sarah Latham please come to the desk?

Read and Write Using Key Index