A Map is a type of fast key lookup data structure that offers a flexible means of indexing into its individual elements. Unlike most array data structures in the MATLAB® software that only allow access to the elements by means of integer indices, the indices for a Map can be nearly any scalar numeric value or a character string.
Indices into the elements of a Map are called keys. These keys, along with the data values associated with them, are stored within the Map. Each entry of a Map contains exactly one unique key and its corresponding value. Indexing into the Map of rainfall statistics shown below with a string representing the month of August yields the value internally associated with that month, 37.3.
Keys are not restricted to integers as they are with other arrays. Specifically, a key may be any of the following types:
1-by-N character array
Scalar real double or single
Signed or unsigned scalar integer
The values stored in a Map can be of any type. This includes arrays of numeric values, structures, cells, strings, objects, or other Maps.