MatrixQ¶

Status: Stable

documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

Description¶

MatrixQ[expr]

gives True if expr is a list of lists that can represent a matrix, and gives False otherwise.

MatrixQ[expr, test]

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,

MatrixQ[expr, NumberQ] tests whether expr is a numerical matrix.

Notes

containing no elements that are themselves lists.

Examples (2)¶

Every input below was run against the current Mathilda build and its output recorded.

Applications (2)¶

In[1]:= MatrixQ[{{1, 2}, {3, 4}}]
Out[1]= True

In[2]:= MatrixQ[{1, 2, 3}]
Out[2]= False

Implementation notes¶

builtin_matrixq (src/list.c) returns True when the argument is a non-empty List of equal-length List rows whose entries are non-lists; with an optional test argument each entry must instead satisfy test[entry] (evaluated to True). Any ragged row, empty outer list, or failing entry yields False.

Attributes: Protected.

References¶

See also: ListQ, VectorQ, List

Source: src/list.c
Specification: docs/spec/builtins/expression-information.md
Tests: tests/test_list.c
Tests: tests/test_ml_pca.c
Tests: tests/test_ndarray.c
Tests: tests/test_ndarray_linalg.c

Notes & additional examples¶

Notes¶

MatrixQ is True for a list of equal-length lists; a flat (rank-1) list is a vector, not a matrix.