percent-of ( ... seq quot: ( ... elt -- ... ? ) -- ... % )

Vocabulary

sequences.extras

Inputs

seq	a sequence
quot	a quotation with stack effect ( ... elt -- ... ? )

Outputs

%	a rational

Word description

Outputs the fraction of elements in the sequence for which the predicate quotation matches.

Examples

USING: math ranges prettyprint sequences.extras ; 100 [1..b] [ even? ] percent-of .
1/2

Definition

USING: kernel math sequences ;

IN: sequences.extras

: percent-of ( ... seq quot: ( ... elt -- ... ? ) -- ... % )
    over length 0 =
    [ 2drop 0 ] [ over [ count ] [ length ] bi* / ] if ; inline