VectorQ¶

Status: Stable

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

Description¶

VectorQ[expr]

gives True if expr is a list, none of whose elements are themselves lists, and gives False otherwise.

VectorQ[expr, test]

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

VectorQ[expr, NumberQ]

tests whether expr is a vector of numbers.

Examples (2)¶

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

Applications (2)¶

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

In[2]:= VectorQ[{{1, 2}, {3, 4}}]
Out[2]= False

Implementation notes¶

builtin_vectorq (src/list.c) returns True when the argument is a List (is_listq) none of whose elements is itself a List. With a second argument test, each element is instead required to satisfy test[elem] (evaluated, must yield True). Returns False as soon as a check fails.

Attributes: Protected.

References¶

See also: ListQ, MatrixQ, List

Source: src/info.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_packed_list.c

Notes & additional examples¶

Notes¶

VectorQ is True for a flat list none of whose elements are themselves lists; a list of lists (a matrix) is not a vector.