MatrixQ
Usage Message: 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. Attributes[MatrixQ] = {Protected} Related Symbols List
, TensorRank
, VectorQ
Notes: MatrixQ[expr] returns True
if - expr has a head of List
- expr has at least one element (row)
- each row has a head of List
- all rows have the same length
- none of the row elements have a head of List
Otherwise, MatrixQ[expr] returns False
. MatrixQ[expr, test] returns True
only if test[eij] evaluates to True
for each element eij in each row of expr. Here are some simple examples.
In[1]:= MatrixQ[{{1}, {2}}]
Out[1]= True
In[2]:= MatrixQ[{{1}, {2, 3}}]
Out[2]= False
The special case MatrixQ[expr, NumberQ] is optimized by calling NumberQ
internally, rather than through ordinary evaluation. If you want this test to go through the evaluator, such as if you have modified the definition of NumberQ
, then you can use MatrixQ[expr, NumberQ[#] &] instead.
Additional Online Documentation:
Mathematica 3.0
http://documents.wolfram.com/v3/RefGuide/MatrixQ.html
Mathematica 4.0
http://documents.wolfram.com/v4/RefGuide/MatrixQ.html
Questions or comments? Send email to support@wolfram.com.
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