Sure. No need to do any recursion here. Just count in binary. Here is a version that creates a closure (an anonymous subroutine that holds the needed data inside of itself -- sort of like a tiny "object") that returns the next combination each time it is called:

```sub combinations {
my @list= @_;
my @pick= (0) x @list;
return sub {
my \$i= 0;
while( 1 < ++\$pick[\$i]  ) {
\$pick[\$i]= 0;
return   if  \$#pick < ++\$i;
}
return @list[ grep \$pick[\$_], 0..\$#pick ];
};
}
my \$next= combinations( 50..59 );
my @comb;
while(  @comb= \$next->()  ) {
# do work with @comb here
}
# Note that the empty set is a valid combination but is
# the last combination returned which also indicates "no
# more combinations left.  So the above loop doesn't bother
# processing the empty list.  If you want to process the
# empty set, then use:
my @comb;
do {
# do work with @comb here
} while(  @comb= \$next->() );
[download]```

Update: My code finds combinations but the original code finds permutations even though the author asked for combinations. (See (tye)Re: Permutations if you don't know the difference between the two.)

Of course, my favorite way of finding permutations is Permuting with duplicates and no memory.

- tye (but my friends call me "Tye")

In reply to (tye)Re: Finding all Combinations by tye
in thread Finding all Combinations by narse

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