Self-describing numbers: Difference between revisions

=={{header|Factor}}==

<lang factor>USING: kernel math.parser prettyprint sequences ;

IN: rosetta-code.self-describing-numbers

: digits ( n -- seq ) number>string string>digits ;

: digit-count ( seq n -- m ) [ = ] curry count ;

: self-describing-number? ( n -- ? )

digits dup [ digit-count = ] with map-index [ t = ] all? ;

100,000,000 <iota> [ self-describing-number? ] filter .</lang>

{{out}}

<pre>

V{ 1210 2020 21200 3211000 42101000 }

</pre>