- `NC = columns (A)`

Return the number of columns of `A`.

This is equivalent to 'size (A, 2)'.

See also: `rows`, `size`, `length`, `numel`, `isscalar`, `isvector`,
`ismatrix`.

### References

- https://www.mathworks.com/help/matlab/ref/columns.html
- https://octave.sourceforge.io/octave/function/columns.html