Fundamental MATLAB Classes

There are many different data types, or classes, that you can work with in MATLAB^®. You can build matrices and arrays of floating-point and integer data, characters and strings, logical true and false values, and so on. Function handles connect your code with any MATLAB function regardless of the current scope. Tables, timetables, structures, and cell arrays provide a way to store dissimilar types of data in the same container.

There are 17 fundamental classes in MATLAB. Each of these classes is in the form of a matrix or array. With the exception of function handles, this matrix or array is a minimum of 0-by-0 in size and can grow to an n-dimensional array of any size. A function handle is always scalar (1-by-1).

All of the fundamental MATLAB classes are shown in the diagram.

Numeric classes in the MATLAB software include signed and unsigned integers, and single- and double-precision floating-point numbers. By default, MATLAB stores all numeric values as double-precision floating point. (You cannot change the default type and precision.) You can choose to store any number, or array of numbers, as integers or as single-precision. Integer and single-precision arrays offer more memory-efficient storage than double-precision.

All numeric types support basic array operations, such as subscripting, reshaping, and mathematical operations.

You can create two-dimensional double and logical matrices using one of two storage formats: full or sparse. For matrices with mostly zero-valued elements, a sparse matrix requires a fraction of the storage space required for an equivalent full matrix. Sparse matrices invoke methods especially tailored to solve sparse problems.

These classes require different amounts of storage, the smallest being a logical value or 8-bit integer which requires only 1 byte. It is important to keep this minimum size in mind if you work on data in files that were written using a precision smaller than 8 bits.

The following table describes the fundamental classes in more detail.

Class Name	Documentation	Intended Use
double, single	Floating-Point Numbers	Required for fractional numeric data. Double and Single precision. Use realmin and realmax to show range of values. Two-dimensional arrays can be sparse. Default numeric type in MATLAB.
int8, uint8, int16, uint16, int32, uint32, int64, uint64	Integers	Use for signed and unsigned whole numbers. More efficient use of memory. Use intmin and intmax to show range of values. Choose from 4 sizes (8, 16, 32, and 64 bits).
char, string	Characters and Strings	Data type for text. Native or Unicode®. Converts to/from numeric. Use with regular expressions. For multiple character arrays, use cell arrays. You also can store text in string arrays. For more information, see string.
logical	Logical (Boolean) Operations	Use in relational conditions or to test state. Can have one of two values: true or false. Also useful in array indexing. Two-dimensional arrays can be sparse.
function_handle	Function Handles	Pointer to a function. Enables passing a function to another function Can also call functions outside usual scope. Use to specify graphics callback functions. Save to MAT-file and restore later.
table, timetable	Tables, Timetables	Tables are rectangular containers for mixed-type, column-oriented data. Tables have row and variable names that identify contents. Timetables also provide storage for data in a table with rows labeled by time. Timetable functions can synchronize, resample, or aggregate timestamped data. Use the properties of a table or timetable to store metadata such as variable units. Manipulation of elements similar to numeric or logical arrays. Access data by numeric or named index. Can select a subset of data and preserve the table container or can extract the data from a table.
struct	Structures	Fields store arrays of varying classes and sizes. Access one or all fields/indices in single operation. Field names identify contents. Method of passing function arguments. Use in comma-separated lists. More memory required for overhead
cell	Cell Arrays	Cells store arrays of varying classes and sizes. Allows freedom to package data as you want. Manipulation of elements is similar to numeric or logical arrays. Method of passing function arguments. Use in comma-separated lists. More memory required for overhead

Related Topics

• Valid Combinations of Unlike Classes

External Websites

• Programming: Organizing Data (MathWorks Teaching Resources)