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The following functions allow you to determine the size of a variable or
expression. These functions are defined for all objects. They return
−1 when the operation doesn't make sense. For example, Octave's
data structure type doesn't have rows or columns, so the `rows`

and
`columns`

functions return −1 for structure arguments.

— Built-in Function: **length** (`a`)

Return the `length' of the object

a. For matrix objects, the length is the number of rows or columns, whichever is greater (this odd definition is used for compatibility with Matlab).

— Built-in Function: **size** (`a, n`)

Return the number rows and columns of

a.With one input argument and one output argument, the result is returned in a row vector. If there are multiple output arguments, the number of rows is assigned to the first, and the number of columns to the second, etc. For example,

size ([1, 2; 3, 4; 5, 6]) => [ 3, 2 ] [nr, nc] = size ([1, 2; 3, 4; 5, 6]) => nr = 3 => nc = 2If given a second argument,

`size`

will return the size of the corresponding dimension. For examplesize ([1, 2; 3, 4; 5, 6], 2) => 2returns the number of columns in the given matrix.