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BUILT-IN MATHEMATICA SYMBOL

MatrixQ

MatrixQ[expr]
gives True if expr is a list of lists or a two-dimensional SparseArray object that can represent a matrix, and gives False otherwise.

gives True only if test yields True when applied to each of the matrix elements in expr.

MatrixQ[expr] gives True only if expr is a list and each of its elements is a list of the same length, containing no elements that are themselves lists, or if expr is a two-dimensional SparseArray object.

Test of whether an object is a matrix:

These are not matrices:

Use tests to generalize and specialize:

Test of whether an object is a matrix:

Out[1]=

Out[2]=

These are not matrices:

Out[1]=

Out[2]=

Use tests to generalize and specialize:

Out[1]=

Out[2]=

Test if a matrix has positive (real) entries:

Test if a matrix has real numeric entries:

Faster test for real-valued numbers:

Define a function that only evaluates for explicit matrices:

This represents the Hermitian part of a matrix symbolically:

This gets the Hermitian part explicitly:

MatrixQ is a special case of ArrayQ:

A matrix is made up of vectors of equal length: