cast - Convert variable to different data type - MATLAB (original) (raw)

Convert variable to different data type

Syntax

Description

[B](#mw%5Fe6e82388-a147-4fd8-a455-0a64181b5fc9) = cast([A](#mw%5Fbafb4d74-9bd5-4b33-b129-8f4000f6efbd),[newclass](#mw%5F95e4dd69-4cf8-41a9-a746-08560de273e1)) returns the data in A converted to the data type (class)newclass, where newclass is the name of a built-in data type compatible with A. Any values in A that are outside the range of newclass are truncated in B to the nearest endpoint.

When converting a floating-point number to an integer, the cast function rounds the number to the nearest integer. If the floating-point number has a fractional part of exactly 0.5, then it rounds away from zero to the integer with larger magnitude.

example

[B](#mw%5Fe6e82388-a147-4fd8-a455-0a64181b5fc9) = cast([A](#mw%5Fbafb4d74-9bd5-4b33-b129-8f4000f6efbd),like=[p](#mw%5F9aefb75b-feb7-46a1-a99f-ff7851520618)) converts A to the same data type and sparsity as the variablep. The complexity (real or complex) of B is determined by both A and p. If bothA and p are real, then B is also real. Otherwise, B is complex.

example

Examples

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Convert int8 values to uint8.

Define a vector of 8-bit integers.

Convert a to unsigned 8-bit integers. The –5 value outside the range of uint8 is truncated to 0.

b = 1×2 uint8 row vector

0 5

Create a 1-by-3 vector of 32-bit signed integers.

A = 1×3 int32 row vector

-12 34 56

Create a complex number of the data type double.

Convert A to the same data type and complexity as the variable p.

B = 1×3 complex

-12.0000 + 0.0000i 34.0000 + 0.0000i 56.0000 + 0.0000i

Create a 2-by-3 matrix of zeros whose elements are 32-bit unsigned integers.

A = 2×3 uint32 matrix

0 0 0 0 0 0

Create a 2-by-2 sparse matrix of the data type double.

p = 2×2 sparse double matrix (1 nonzero) (2,2) 3.1416

Convert A to the same data type and sparsity as the variable p.

B = 2×3 sparse double matrix All zero

Input Arguments

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Input array, specified as a scalar, vector, matrix, or multidimensional array. The data type of A can be a built-in data type or other data type that supports conversion to the specified new data type.

New class, specified as "single", "double","int8", "int16", "int32","int64", "uint8", "uint16","uint32", "uint64","logical", or "char".

Prototype, specified as a scalar, vector, matrix, or multidimensional array. The data type of p can be a built-in data type or other compatible data type that supports conversion from the input data type.

Output Arguments

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Output array, returned as a scalar, vector, matrix, or multidimensional array.

Extended Capabilities

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Usage notes and limitations:

Enumeration inputs must be scalar valued at compile time. Arrays of enumerations are not supported.

Usage notes and limitations:

Enumeration inputs must be scalar valued at compile time. Arrays of enumerations are not supported.

The cast function supports GPU array input with these usage notes and limitations:

For the syntax B = cast(A,like=p), the outputB is a gpuArray if and only ifp is a gpuArray.

For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Usage notes and limitations:

For the syntax B = cast(A,like=p), the outputB is a distributed array if and only if p is a distributed array.

For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced before R2006a

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Starting in R2022a, the syntax cast(A,like=p) returns output consistent with the prototype p when the data type ofp is a subclass of MATLAB® numeric types.

For example, this code now returns an output that has the same data type asp:

p = matlab.lang.OnOffSwitchState.on; x = cast(1,like=p)

x =

OnOffSwitchState enumeration

on

In previous releases, the code returns x = 1 with data type logical.

Starting in R2021b, the newclass input argument of the syntaxcast(A,newclass) is case-sensitive. You must specifynewclass as a character vector or a string of lowercase letters that represents the new data type.

For example, to convert a double value to the int8 data type, you must use cast(1.234,"int8"). The commandcast(1.234,"Int8") now errors.