#### 17.3.11 length [Function]

`length` sequence ⇒ n

#### Arguments and Values::

sequence—a proper sequence.

n—a non-negative integer.

#### Description::

Returns the number of elements in sequence.

If sequence is a vector with a fill pointer, the active length as specified by the fill pointer is returned.

#### Examples::

     (length "abc") ⇒  3
     (setq str (make-array '(3) :element-type 'character
                                :initial-contents "abc"
                                :fill-pointer t)) ⇒  "abc"
     (length str) ⇒  3
     (setf (fill-pointer str) 2) ⇒  2
     (length str) ⇒  2

#### Exceptional Situations::

Should be prepared to signal an error of type type-error if sequence is not a proper sequence.

#### See Also::

list-length , sequence