Golf: Factorials

[srawls]

This is geared more towards the beginner, to give him a chance to golf, but if you are more advanced and still want to post, than you can just post your code in a 'black box'.

The problem: Passed to your function is a list of numbers, and the function should return a list of those number's factorials. (factorial of 5 is 5*4*3*2*1).

Example:

@a = factorial(5); $a[0] = 120<br>
@a = factorial(5,3,10); $a[0..2] = (120,6,3628800)

Again, this is meant for beggining to intermidately skilled programmers, but if you are better than that, you can see if you can beat my humble (and probably futile) atempt at the golf. (Click readmore to see my code).

sub f {
push@a,eval join'*',1..$_ for@_;@a
}

The 15 year old, freshman programmer,
Stephen Rawls

[japhy]

sub f {map{eval join'*',1..$_}@_}



japhy -- Perl and Regex Hacker

[mr.nick]

I don't know ... am I a beginner? :) I guess at golf, I am.

sub f{map{eval join"*",1..$_}@_;}

33 chars. Duh! Identical as someone else's answer ...

[bobione]

32 characters if you delete that last ';'...


sub f{map{eval join"*",1..$_}@_}


Update: Sorry it's the same as japhy... nothing new.

BobiOne KenoBi ;)

[Discipulus]

sub fact{
            (map{$_[0]*=$_}1..$_[0]-1)[-1]||1   # 33

          # only 30 char for numbers bigger than 1
          # (map{$_[0]*=$_}1..$_[0]-1)[-1]


}



L*
PS some solutions above fails with the number zero that must return 1

PPS in addition, negatives numbers must return undef or Error

perl -e "sub fact{$x=$_;$x<0?'E':(map{$x*=$_}1..$x-1)[-1]||1} print ma
+p{fact($_),qq(\n)}@ARGV " 0 1 3 -1

1
1
6
E

[Anonymous Monk]

31 characters
$a=1;print$a*=$b+=1,$/for 0..10

[choroba]

Easy to make it 30 with

$a=1;print$a*=$b+=1,$/for a..k

[Athanasius]

24 characters using say and an unused punctuation variable:

13:38 >perl -E "$a=1;say$a*=++$}for a..k"
1
2
6
24
120
720
5040
40320
362880
3628800
39916800

13:38 >

:-)