IsMatrix

Tests whether m is a non-empty, non-ragged rank-2 List of Lists, optionally with every entry satisfying test.

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

IsMatrix(m)True if m is a List of Lists, all the same length, none containing a further List

IsMatrix(m, test)as above, and test holds of every entry

Typed signatures

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

Domain: Collections

Details

A ragged List of Lists (rows of different lengths), an empty List, or anything of rank other than exactly 2, is False.

Examples

Basic #

\mathrm{IsMatrix}(\bigl\lbrack\bigl\lbrack1, 2\bigr\rbrack, \bigl\lbrack3, 4\bigr\rbrack\bigr\rbrack)

Out

\mathrm{True}

Symbolic entries are fine: only the rectangular shape matters

\mathrm{IsMatrix}(\bigl\lbrack\bigl\lbrack a, b\bigr\rbrack, \bigl\lbrack3, 4\bigr\rbrack\bigr\rbrack)

Out

\mathrm{True}

Rows of unequal length do not form a matrix

\mathrm{IsMatrix}(\bigl\lbrack\bigl\lbrack1\bigr\rbrack, \bigl\lbrack2, 3\bigr\rbrack\bigr\rbrack)

Out

\mathrm{False}

A rank-3 array is deeper than a matrix

\mathrm{IsMatrix}(\mathrm{Array}(a, \bigl\lbrack2, 2, 2\bigr\rbrack))

Out

\mathrm{False}

Scope #

\mathrm{IsMatrix}(\bigl\lbrack1, 2, 3\bigr\rbrack)

Out

\mathrm{False}

\mathrm{IsMatrix}(\bigl\lbrack\bigl\lbrack1, 2\bigr\rbrack, \bigl\lbrack3\bigr\rbrack\bigr\rbrack)

Out

\mathrm{False}

\mathrm{IsMatrix}(\bigl\lbrack\bigr\rbrack)

Out

\mathrm{False}

\mathrm{IsMatrix}(\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 matrices

\bigl\lbrack\mathrm{IsMatrix}(\mathrm{mat}), \mathrm{IsMatrix}(\mathrm{expr})\bigr\rbrack

Out

\bigl\lbrack\mathrm{False}, \mathrm{False}\bigr\rbrack

About