Your skill will accomplish what the force of many cannot |
|
PerlMonks |
most efficient way to implement "A without B"by telcontar (Beadle) |
on Apr 09, 2005 at 17:55 UTC ( [id://446267]=perlquestion: print w/replies, xml ) | Need Help?? |
telcontar has asked for the wisdom of the Perl Monks concerning the following question:
Let's say you have two lists, @a and @b, and all elements of @b are contained in @a. How do you get "@a without @b"?
Of course, one could sort both lists, iterate through the elements of @a, have an index for @b, and push elements in @a to an array @c if the element in @a is not at that position in @b. But that seems rather tedious.
For instance,
I'm sure this can be done in a somewhat more efficient (perl-ish *g) way ... like this:
This should work if @b is already sorted. I'm sure it can be done in better ways .. I'm brand-new at Perl after all. John
Back to
Seekers of Perl Wisdom
|
|