Data Type Conversion

Convert between numeric arrays, strings and character arrays, dates and times, cell arrays, structures, or tables

MATLAB^®有许多函数将值从一个数据type to another for use in different contexts. For example, you can convert numbers to text and then append them to plot labels or file names. You can represent numbers as their hexadecimal or binary values. MATLAB provides functions for conversions between numeric arrays, strings and character arrays, andcategorical,datetime, anddurationarrays. Also, you can convert between the data types that group data in containers, such as cell arrays, structures, tables, and timetables. In those cases, the data values remain the same, but they are stored and accessed in a different type of container.

Functions

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Numbers and Text

Convert Numbers to Text

`string`	String array
`char`	Character array
`cellstr`	Convert to cell array of character vectors
`int2str`	Convert integers to characters
`mat2str`	Convert matrix to characters
`num2str`	Convert numbers to character array

Convert Text to Numbers

`str2double`	Convert strings to double precision values
`str2num`	Convert character array or string to numeric array
`native2unicode`	Convert numeric bytes toUnicodecharacter representation
`unicode2native`	ConvertUnicodecharacter representation to numeric bytes

Hexadecimal and Binary Numbers

`base2dec`	Convert text representation of base-`n`integer to double value
`bin2dec`	Convert text representation of binary integer to double value
`dec2base`	Convert decimal integer to its base-`n`representation
`dec2bin`	Convert decimal integer to its binary representation
`dec2hex`	Convert decimal integer to its hexadecimal representation
`hex2dec`	Convert text representation of hexadecimal integer to double value
`hex2num`	ConvertIEEEhexadecimal format to double-precision number
`num2hex`	Convert single- and double-precision numbers toIEEEhexadecimal format

Dates and Times

Convert Values to Dates and Times

`datetime`	Arrays that represent points in time
`duration`	Lengths of time in fixed-length units

Convert Dates and Times to Text

`string`	String array
`char`	Character array
`cellstr`	Convert to cell array of character vectors

Categorical Arrays, Tables, and Timetables

Categorical Arrays

categorical Array that contains values assigned to categories

Tables

`table2array`	Convert table to homogeneous array
`table2cell`	Convert table to cell array
`table2struct`	Convert table to structure array
`array2table`	Convert homogeneous array to table
`cell2table`	Convert cell array to table
`struct2table`	Convert structure array to table

Timetables

`array2timetable`	Convert homogeneous array to timetable
`table2timetable`	Convert table to timetable
`timetable2table`	Convert timetable to table

Cell Arrays and Structures

`cell2mat`	Convert cell array to ordinary array of the underlying data type
`cell2struct`	Convert cell array to structure array
`mat2cell`	Convert array to cell array whose cells contain subarrays
`num2cell`	Convert array to cell array with consistently sized cells
`struct2cell`	Convert structure to cell array

Topics

Convert Text to Numeric Values

Convert text to arrays of numeric values. Text can represent floating-point values, dates and times, and hexadecimal and binary numbers. If text represents dates and times, then you can convert the text to datetime or duration values.

Convert Numeric Values to Text

Convert numeric values to text. Text can represent floating-point values, either with or without exponential notation, or hexadecimal or binary digits. Use these conversions to add numbers to text such as plot labels or titles.

Unicode and ASCII Values

MATLAB stores all characters as Unicode characters. Both strings and character vectors use the same encoding. You can convert characters to their Unicode code values, and numbers to characters.

Hexadecimal and Binary Values

Specify hexadecimal and binary values either as literals or as text. Hexadecimal and binary literals are stored as integers. You can convert text representing hexadecimal and binary values to numbers, and numbers to text representations.

Convert Between Datetime Arrays, Numbers, and Text

Whiledatetimeis the recommended data type for representing points in time, you might need to work with dates and time stored as date strings, date vectors, and serial date numbers.

Convert Text in Table Variables to Categorical

这个例子展示了如何将一个变量中table from a cell array of character vectors to a categorical array.

Valid Combinations of Unlike Classes

If you include elements of unlike classes in a matrix, MATLAB converts some elements so that all elements of the resulting matrix are of the same type. Data type conversion is done with respect to a preset precedence of classes.