flipud

Flip array up to down

Syntax

B = flipud(A)

Description

B = flipud(A) returns A with its rows flipped in the up-down direction (that is, about a horizontal axis).

If A is a column vector, then flipud(A) returns a vector of the same length with the order of its elements reversed. If A is a row vector, then flipud(A) simply returns A. For multidimensional arrays, flipud operates on the planes formed by the first and second dimensions.

Examples

Flip Column Vector

Create a column vector.

A=(1:10)'

A = 10×1

     1
     2
     3
     4
     5
     6
     7
     8
     9
    10

Use flipud to flip the elements of A in the vertical direction.

B = flipud(A)

B = 10×1

    10
     9
     8
     7
     6
     5
     4
     3
     2
     1

The order of the elements in B is reversed compared to A.

Flip Cell Array of Characters

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

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

A = 3x3 cell
    {'a'}    {'b'}    {'c'}
    {'d'}    {'e'}    {'f'}
    {'g'}    {'h'}    {'i'}

Change the order of the rows in the vertical direction by using flipud.

B = flipud(A)

B = 3x3 cell
    {'g'}    {'h'}    {'i'}
    {'d'}    {'e'}    {'f'}
    {'a'}    {'b'}    {'c'}

The order of the first and third rows of A is switched in B, while the second row remains unchanged.

Flip Multidimensional Array

Create a multidimensional array.

A = cat(3, [1 2; 3 4], [5 6; 7 8])

A = 
A(:,:,1) =

     1     2
     3     4


A(:,:,2) =

     5     6
     7     8

A is an array of size 2-by-2-by-2.

Flip the elements on each page of A in the vertical direction.

B = flipud(A)

B = 
B(:,:,1) =

     3     4
     1     2


B(:,:,2) =

     7     8
     5     6

The result, B, is the same size as A, but the vertical order of the elements is flipped. The operation flips the elements on each page independently.

Input Arguments

A — Input array

vector | matrix | multidimensional array | table | timetable

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

Data Types: double | single | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | char | string | struct | cell | table | timetable | categorical | datetime | duration | calendarDuration

Complex Number Support: Yes

Tips

• flipud(A) is equivalent to flip(A,1).

• Use the fliplr function to flip arrays in the horizontal direction (that is, about a vertical axis).

• The flip function can flip arrays in any direction.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• Does not support cell arrays.

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 flipud 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