IsArray

Tests whether t is a List with a uniform (non-ragged) shape at every depth, any rank, optionally with every leaf satisfying test.

✓ checked against that system · ! checked, with disagreements (hover a chip)Wolfram LanguageArrayQ✓↗

IsArray(t)True if t is a List whose nesting is rectangular at every level (a "full array")

IsArray(t, test)as above, and test holds of every leaf

Typed signatures

Type	Package	Applies
(any, function?) -> boolean	combinatorics	always

Domain: Collections

Details

• Generalizes IsVector (rank 1) and IsMatrix (rank 2) to any rank, including a flat List (rank 1) and a ragged List (False, same as the other two).
• A non-List is False — a bare scalar isn't an array of rank 0 here.

Examples

Basic #

live ↗

In$\mathrm{IsArray}(\bigl\lbrack\bigl\lbrack1, 2\bigr\rbrack, \bigl\lbrack3, 4\bigr\rbrack\bigr\rbrack)$Out$\mathrm{True}$

A flat list is a rank-1 array

live ↗

In$\mathrm{IsArray}(\bigl\lbrack1, 2, 3, 4\bigr\rbrack)$Out$\mathrm{True}$

A ragged list with a nested element is not a full array

live ↗

In$\mathrm{IsArray}(\bigl\lbrack1, 2, \bigl\lbrack3\bigr\rbrack, 4\bigr\rbrack)$Out$\mathrm{False}$

Scope #

live ↗

In$\mathrm{IsArray}(\bigl\lbrack\bigl\lbrack1, 2\bigr\rbrack, \bigl\lbrack3\bigr\rbrack\bigr\rbrack)$Out$\mathrm{False}$

live ↗

In$\mathrm{IsArray}(\bigl\lbrack1, 2, 3\bigr\rbrack)$Out$\mathrm{True}$

live ↗

In$\mathrm{IsArray}(3)$Out$\mathrm{False}$

live ↗

In$\mathrm{IsArray}(\bigl\lbrack\bigl\lbrack2, 4\bigr\rbrack, \bigl\lbrack6, 8\bigr\rbrack\bigr\rbrack, \mathrm{IsEven})$Out$\mathrm{True}$

Properties #

Undefined symbols are not known to be arrays

live ↗

In$\bigl\lbrack\mathrm{IsArray}(\mathrm{mat}), \mathrm{IsArray}(\mathrm{expr})\bigr\rbrack$Out$\bigl\lbrack\mathrm{False}, \mathrm{False}\bigr\rbrack$

About

Examples	8
Checked against	Wolfram Language 8 agree
Crosswalk	Wolfram Language

See also: IsVector, IsMatrix