NaN - Create array of all NaN values - MATLAB (original) (raw)

Create array of all NaN values

Syntax

Description

[X](#mw%5Fafb116f8-769e-4cee-bc31-1bb62afb480c) = NaN returns the scalar representation of "not a number". Operations return NaN when they have undefined numeric results, such as 0/0 or0*Inf.

[X](#mw%5Fafb116f8-769e-4cee-bc31-1bb62afb480c) = NaN([n](#d126e1160660)) returns ann-by-n matrix of NaN values.

example

[X](#mw%5Fafb116f8-769e-4cee-bc31-1bb62afb480c) = NaN([sz1,...,szN](#mw%5Fb597fd4e-0d30-4b48-8feb-76483f094a3c)) returns an sz1-by-...-by-szN array ofNaN values, where sz1,...,szN indicate the size of each dimension. For example, NaN(3,4) returns a 3-by-4 matrix.

example

[X](#mw%5Fafb116f8-769e-4cee-bc31-1bb62afb480c) = NaN([sz](#mw%5Ffdda7c2e-68e5-4498-8776-7f6a5f3a83ce)) returns an array of NaN values, where the size vector sz defines size(X). For example, NaN([3 4]) returns a 3-by-4 matrix.

example

[X](#mw%5Fafb116f8-769e-4cee-bc31-1bb62afb480c) = NaN(___,[typename](#mw%5F218f8ea7-8bb3-4402-adaf-89a7accc51ce)) returns an array of NaN values of data typetypename, which can be either "single" or"double".

example

[X](#mw%5Fafb116f8-769e-4cee-bc31-1bb62afb480c) = NaN(___,like=[p](#mw%5F6bb64174-2f2b-47dc-a3d3-7a49c3f3aa80)) returns an array of NaN values of the same data type, sparsity, and complexity (real or complex) as p. You can specifytypename or like but not both.

example

Examples

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Create a 3-by-3 matrix of NaN values.

X = 3×3

NaN NaN NaN NaN NaN NaN NaN NaN NaN

Create a 2-by-3-by-4 array of NaN values and display its size.

Create an array of NaN values that is the same size as an existing array.

A = [1 4; 2 5; 3 6]; sz = size(A); X = NaN(sz)

X = 3×2

NaN NaN NaN NaN NaN NaN

It is a common pattern to combine the previous two lines of code into a single line.

Create a 1-by-3 vector of NaN values whose elements are of type single.

X = 1×3 single row vector

NaN NaN NaN

You can also specify the output type based on the type of another variable. Create a variable p of type single. Then, create a vector of NaN values with the same size and type as p.

p = single([1 2 3]); X = NaN(size(p),like=p)

X = 1×3 single row vector

NaN NaN NaN

Input Arguments

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Size of square matrix, specified as an integer.

• If n is 0, then X is an empty matrix.
• If n is negative, then it is treated as 0.

Data Types: double | single | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Size of each dimension in a list, specified as separate integer arguments.

• If the size of any dimension is 0, then X is an empty array.
• If the size of any dimension is negative, then it is treated as 0.
• Beyond the second dimension, NaN ignores trailing dimensions of length 1. For example, NaN(3,1,1) creates a 3-by-1 vector of NaN values.

Data Types: double | single | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Size of each dimension in a vector, specified as a row vector of integers.

• If the size of any dimension is 0, then X is an empty array.
• If the size of any dimension is negative, then it is treated as 0.
• Beyond the second dimension, NaN ignores trailing dimensions of length 1. For example, NaN([3 1 1]) creates a 3-by-1 vector of NaN values.

Data Types: double | single | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Data type to create, specified as "double" or"single".

Prototype of array to create, specified as an array.

Data Types: double | single
Complex Number Support: Yes

Output Arguments

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Array of NaN values, returned as a scalar, vector, matrix, or multidimensional array.

Tips

• X = NaN returns the scalar, type double, IEEE® representation of "not a number". The exact bit-wise hexadecimal representation of this value is fff8000000000000. MATLAB® preserves the "not a number" status of alternate NaN representations and treats all representations equivalently. In some special cases, due to hardware limitations for example, MATLAB does not preserve the exact bit pattern of the alternate representations during computation, and instead uses the canonical NaN bit pattern previously described.
• NaN values are not equal to each other. As a result, comparison operations involving NaN return false, except for the not equal operator ~=. For example, NaN == NaN returns logical 0 (false), but NaN ~= NaN returns logical 1 (true).
• NaN values in a vector are treated as different unique elements. For example, unique([1 1 NaN NaN]) returns the row vector [1 NaN NaN].
• Use the isnan or ismissing function to detectNaN values in an array. Use the anynan oranymissing function to determine if any array element isNaN. Use the rmmissing function to detect and remove NaN values, and the fillmissing function to detect NaN values and replace them with non-NaN values.

Extended Capabilities

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Usage notes and limitations:

• Dimensions must be real, nonnegative, integers.

Usage notes and limitations:

• Dimensions must be real, nonnegative, integers.

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

• You can specify typename as 'gpuArray'. If you specifytypename as 'gpuArray', the default underlying type of the array is double.
  To create a GPU array with underlying type datatype, specify the underlying type as an additional argument before typename. For example, X = NaN(3,datatype,'gpuArray') creates a 3-by-3 GPU array of all NaN values with underlying typedatatype.
  You can specify the underlying type datatype as one of these options:
  • 'double'
  • 'single'
• You can also specify the numeric variable p as agpuArray.
  If you specify p as a gpuArray, the underlying type of the returned array is the same as p.

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

Usage notes and limitations:

• You can specify typename as 'codistributed' or'distributed'. If you specify typename as'codistributed' or 'distributed', the default underlying type of the returned array is double.
  To create a distributed or codistributed array with underlying typedatatype, specify the underlying type as an additional argument before typename. For example, X = NaN(3,datatype,'distributed') creates a 3-by-3 distributed array of allNaN values with underlying type datatype.
  You can specify the underlying type datatype as one of these options:
  • 'double'
  • 'single'
• You can also specify p as a codistributed or distributed array.
  If you specify p as a codistributed ordistributed array, the underlying type of the returned array is the same as p.
• For additional codistributed syntaxes, see NaN (codistributed) (Parallel Computing Toolbox).

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

Version History

Introduced before R2006a