shiftdim - Shift array dimensions - MATLAB (original) (raw)
Syntax
Description
[B](#mw%5F1f3b4325-c8ed-48c1-b066-2b2d8fbd87bc) = shiftdim([A](#mw%5Fbebd5d37-ee00-4fe8-b943-62ed88283e50),[n](#d126e1651421)) shifts the dimensions of an array A by n positions.shiftdim shifts the dimensions to the left when n is a positive integer and to the right when n is a negative integer. For example, if A is a 2-by-3-by-4 array, thenshiftdim(A,2) returns a 4-by-2-by-3 array.
[B](#mw%5F1f3b4325-c8ed-48c1-b066-2b2d8fbd87bc) = shiftdim([A](#mw%5Fbebd5d37-ee00-4fe8-b943-62ed88283e50)) returns an array with the same elements as A but with leading dimensions of length 1 removed.
[[B](#mw%5F1f3b4325-c8ed-48c1-b066-2b2d8fbd87bc),[m](#mw%5Fb94339eb-9659-43dd-8745-4178a1e66ea0)] = shiftdim([A](#mw%5Fbebd5d37-ee00-4fe8-b943-62ed88283e50)) also returns the number of dimensions of length 1 that were removed.
Examples
4-D Array
Create a 4-by-2-by-3-by-5 array. Shift the dimensions 2 positions to the left, wrapping the first 2 lengths to the last 2 dimensions.
A = rand(4,2,3,5); B = shiftdim(A,2); size(B)
Shift the dimensions 2 positions to the right, resulting in 2 leading dimensions of length 1. Shifting to the right does not wrap the dimension lengths.
C = shiftdim(A,-2); size(C)
Shift Array Dimensions
Shift the dimensions of an array.
Compute a 5-D array A, and remove the leading dimensions of length 1. The shiftdim function shifts 2 dimensions and returns the 3-D array B.
A = rand(1,1,3,2,4); [B,nshifts] = shiftdim(A); nshifts
Shift the dimensions of B twice to the left.
C = shiftdim(B,2); size(C)
Shift the dimensions of C once to the right.
D = shiftdim(C,-1); size(D)
Input Arguments
A — Input array
vector | matrix | multidimensional array
Input array, specified as a vector, matrix, or multidimensional array.
n — Number of positions
integer
Number of dimension positions to shift, specified as an integer. Whenn is positive, shiftdim shifts the dimensions to the left, wrapping the leading dimensions to the end. When n is negative, shiftdim shifts the dimensions to the right, padding additional leading dimensions with length 1.
Output Arguments
B — Output array
vector | matrix | multidimensional array
Output array, specified as a vector, matrix, or multidimensional array.
m — Number of dimensions removed
non-negative integer
Number of dimensions removed, specified as a non-negative integer.shiftdim removes only leading dimensions of length 1.
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Usage notes and limitations:
- Does not support cell arrays for the first argument.
- Second argument must be a constant.
- See Variable-Sizing Restrictions for Code Generation of Toolbox Functions (MATLAB Coder).
Thread-Based Environment
Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.
This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.
GPU Arrays
Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.
The shiftdim function fully supports GPU arrays. To run the function on a GPU, specify the input data as a gpuArray (Parallel Computing Toolbox). For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).
Distributed Arrays
Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.
This function fully supports distributed arrays. For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).
Version History
Introduced before R2006a