AnyTrue

Status: Stable

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

Description

AnyTrue[list, test]

Gives True if test[e] is True for some element e (False for an empty list). Over an association, tests the values.

Examples (6)

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

Basic examples (3)

In[1]:= AllTrue[{2, 4, 6}, EvenQ]
Out[1]= True

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

In[3]:= NoneTrue[{1, 3, 5}, EvenQ]
Out[3]= True

Applications (3)

No element passes, so False

In[4]:= AnyTrue[{1, 3, 5}, EvenQ]
Out[4]= False

One even element is enough for True

In[5]:= AnyTrue[{1, 2, 3}, EvenQ]
Out[5]= True

A pure function as the test

In[6]:= AnyTrue[{1, 3, 5}, # > 4 &]
Out[6]= True

Implementation notes

Algorithm. builtin_any_true is all_any_none_true(res, 1), sharing one quantifier with AllTrue (mode 0) and NoneTrue (mode 2). A bool NDArray with an identity-shaped predicate (TrueQ/Identity) is answered by scanning the raw byte buffer for any set byte — np.any. Otherwise the compiled-predicate path pred_quantify runs, then a visible NDArray is materialised and re-dispatched (ndstruct_delist_repack) and an association is quantified over its values.

The fallback walks the elements building and evaluating test[e]; AnyTrue short-circuits to True on the first test[e] that is True. A result that is neither True nor False makes the whole call stay unevaluated (return NULL), and a Throw from the test propagates. If nothing matches, the result is False — so the empty list gives False.

Data structures. The argument array is borrowed; each test[e] is a built, evaluated, then freed Expr. The bool-buffer path reads only the unsigned char NDArray buffer, closing the sign-predicate → quantifier pipeline without materialising a True/False symbol per element.

Complexity / limits. O(n) tests with early exit (O(1) when an early element matches); the bool scan is O(n) bytes, no allocation. An indeterminate predicate value leaves the call unevaluated.

Attributes: Protected.

References

See also: AllTrue, NoneTrue

• Source: src/funcprog.c
• Specification: docs/spec/builtins/functional-programming.md
• Tests: tests/test_assoc_forms.c
• Tests: tests/test_association.c
• Tests: tests/test_compile.c
• Tests: tests/test_ndarray.c

Notes & additional examples

Notes

AnyTrue[list, test] is True exactly when test[e] is True for at least one element e, and short-circuits on the first match. It is the existential quantifier dual to AllTrue; NoneTrue is its negation. Over an association the values are tested. The empty list gives False.

A test[e] whose value is neither True nor False leaves the whole call unevaluated. Over a boolean packed array with TrueQ or Identity as the test, the answer is an early-exit scan of the raw byte buffer.