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# ismatrix

checks if an object is a non-empty 1D or 2D matrix or array

### Syntax

`tf = ismatrix(x)`

### Arguments

x

scalar,vector, matrix, hypermatrix, list, array of structures or of cells

tf

a boolean

### Description

`ismatrix(x)` returns `%T` (true) if `x` is a scalar (single component), or a vector or a matrix or array with one or 2 dimensions.

 An hypermatrix that would be a matrix after reordering its dimensions is considered as a matrix. To test that `x` is not an hypermatrix or an hyperarray -- whatever are the sizes of its dimensions --, use simply `ndims(x)<3`. `ismatrix([])` returns false.

### Examples

```ismatrix(ones(10,5))
ismatrix(1)
ismatrix(["s" "t" "u"; "t" "s" "u"])
ismatrix(rand(2,1,3)) //because of singleton
ismatrix(rand(2,2,3)) //hypermatrix
s = struct();
ismatrix(s) // Empty structure
clear s
s(1,2).a = 3;
s(1,3).b = %z;
ismatrix(s) // Row array of structures
clear s
s(2,1).a = "w";
s(3,1).b = %t;
iscolumn(s) // Column array of structures
clear s
s(1,2).a = -2;
s(3,1).b = %pi;
ismatrix(s) // 2D not-square array of structures
clear s
s(2,1,2).a = 3;
s(1,1,2).b = "test";
ismatrix(s) // 3D array of structures (with a singleton dim)
clear s
s(1,1,2).a = 3;
s(1,1,3).b = "test";
ismatrix(s) // 3D array of structures (with 2 singleton dims)
clear s
s(2,2,2).a = %f;
s(1,2,1).b = list(%e, %s);
ismatrix(s) // 3D (cubic) array of structures```

• isscalar — check if a variable is a scalar.
• isrow — check if a variable is a row
• iscolumn — check if a variable is a column
• issquare — check if a variable is a square matrix
• isempty — verifica se uma variável é uma matriz vazia ou uma lista vazia
• ndims — número de dimensões de um array

### History

 Versão Descrição 5.5.0 Function ismatrix introduced.