Summary of Matrix and Array Functions :: Matrices and Arrays (MATLAB®)

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Summary of Matrix and Array Functions

This section summarizes the principal functions used in creating and handling matrices. Most of these functions work on multidimensional arrays as well.

Functions to Create a Matrix

Function	Description
`[a,b]` or `[a;b]`	Create a matrix from specified elements, or concatenate matrices together.
`accumarray`	Construct a matrix using accumulation.
`blkdiag`	Construct a block diagonal matrix.
`cat`	Concatenate matrices along the specified dimension.
`diag`	Create a diagonal matrix from a vector.
`horzcat`	Concatenate matrices horizontally.
`magic`	Create a square matrix with rows, columns, and diagonals that add up to the same number.
`ones`	Create a matrix of all ones.
`rand`	Create a matrix of uniformly distributed random numbers.
`repmat`	Create a new matrix by replicating or tiling another.
`vertcat`	Concatenate two or more matrices vertically.
`zeros`	Create a matrix of all zeros.

Functions to Modify the Shape of a Matrix

Function	Description
`ctranspose`	Flip a matrix about the main diagonal and replace each element with its complex conjugate.
`flipdim`	Flip a matrix along the specified dimension.
`fliplr`	Flip a matrix about a vertical axis.
`flipud`	Flip a matrix about a horizontal axis.
`reshape`	Change the dimensions of a matrix.
`rot90`	Rotate a matrix by 90 degrees.
transpose	Flip a matrix about the main diagonal.

Functions to Find the Structure or Shape of a Matrix

Function	Description
`isempty`	Return `true` for 0-by-0 or 0-by-n matrices.
`isscalar`	Return `true` for 1-by-1 matrices.
`issparse`	Return `true` for sparse matrices.
`isvector`	Return `true` for 1-by-n matrices.
`length`	Return the length of a vector.
`ndims`	Return the number of dimensions in a matrix.
`numel`	Return the number of elements in a matrix.
`size`	Return the size of each dimension.

Functions to Determine Class

Function	Description
`iscell`	Return `true` if the matrix is a cell array.
`ischar`	Return `true` if matrix elements are characters or strings.
`isfloat`	Determine if input is a floating point array.
`isinteger`	Determine if input is an integer array.
`islogical`	Return `true` if matrix elements are logicals.
`isnumeric`	Return `true` if matrix elements are numeric.
`isreal`	Return `true` if matrix elements are real numbers.
`isstruct`	Return `true` if matrix elements are MATLAB^® structures.

Functions to Sort and Shift Matrix Elements

Function	Description
`circshift`	Circularly shift matrix contents.
`issorted`	Return `true` if the matrix elements are sorted.
`sort`	Sort elements in ascending or descending order.
`sortrows`	Sort rows in ascending order.

Functions That Work on Diagonals of a Matrix

Function	Description
`blkdiag`	Construct a block diagonal matrix.
`diag`	Return the diagonals of a matrix.
`trace`	Compute the sum of the elements on the main diagonal.
`tril`	Return the lower triangular part of a matrix.
`triu`	Return the upper triangular part of a matrix.

Functions to Change the Indexing Style

Function	Description
`ind2sub`	Convert a linear index to a row-column index.
`sub2ind`	Convert a row-column index to a linear index.

Functions for Working with Multidimensional Arrays

Function	Description
`cat`	Concatenate arrays.
`circshift`	Shift array circularly.
`ipermute`	Inverse permute array dimensions.
`ndgrid`	Generate arrays for `n`-dimensional functions and interpolation.
`ndims`	Return the number of array dimensions.
`permute`	Permute array dimensions.
`shiftdim`	Shift array dimensions.
`squeeze`	Remove singleton dimensions.

Multidimensional Arrays

Built-In Classes (Data Types)