rot90 - Rotate array 90 degrees - MATLAB (original) (raw)

Syntax

Description

B = rot90([A](#bt6yu8i-1-A)) rotates array A counterclockwise by 90 degrees. For multidimensional arrays, rot90 rotates in the plane formed by the first and second dimensions.

example

B = rot90([A](#bt6yu8i-1-A),[k](#bt6yu8i-1-k)) rotates array A counterclockwise by k*90 degrees, where k is an integer.

example

Examples

collapse all

Create a column vector of sequential elements.

Rotate A counterclockwise by 90 degrees using rot90.

The result, B, has the same elements as A but a different orientation.

Create a 3-by-3-by-2 cell array of characters.

A = cat(3,{'a' 'b' 'c';'d' 'e' 'f';'g' 'h' 'i'},{'j' 'k' 'l';'m' 'n' 'o';'p' 'q' 'r'})

A = 3×3×2 cell array A(:,:,1) =

{'a'}    {'b'}    {'c'}
{'d'}    {'e'}    {'f'}
{'g'}    {'h'}    {'i'}

A(:,:,2) =

{'j'}    {'k'}    {'l'}
{'m'}    {'n'}    {'o'}
{'p'}    {'q'}    {'r'}

Rotate the cell array by 270 degrees.

B = 3×3×2 cell array B(:,:,1) =

{'g'}    {'d'}    {'a'}
{'h'}    {'e'}    {'b'}
{'i'}    {'f'}    {'c'}

B(:,:,2) =

{'p'}    {'m'}    {'j'}
{'q'}    {'n'}    {'k'}
{'r'}    {'o'}    {'l'}

The function rotates each page of the array independently. Since a full 360 degree rotation (k = 4) leaves the array unchanged, rot90(A,3) is equivalent to rot90(A,-1).

Input Arguments

collapse all

Input array, specified as a vector, matrix, or multidimensional array.

Rotation constant, specified as an integer. Specify k to rotate by k*90 degrees rather than nesting calls to rot90.

Example: rot90(A,-2) rotates A by -180 degrees and is equivalent to rot90(A,2), which rotates by 180 degrees.

Tips

Use the flip function to flip arrays in any dimension.
When visualizing rotated data, the coordinate system used for plotting can impact the appearance of the rotation. For example, plotting rotated dataB using the command imagesc(B) followed by the command axis xy to automatically choose the_x_ and y axes can cause the data to appear as though it was rotated clockwise instead of counterclockwise.

Extended Capabilities

expand all

Usage notes and limitations:

Does not support cell arrays for the first argument.

Usage notes and limitations:

Does not support cell arrays for the first argument.

The rot90 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).

Version History

Introduced before R2006a