> Is there a quick way to check if an element exists in a list?
As someone else has pointed out, the answer to the question you
asked was the 'grep' function (note: this is a built-in Perl
function, and doesn't require a Unix-style grep utility as someone
suggested on this list recently).
However, you may find that if you put your items in a hash rather
than a list then you could check even more quickly by using the
'exists' function.
eg:
my %checklist = (foo => undef, bar => undef, etc => undef);
if(exists($checklist{foo}) {
...
}
I've set all the values to undef to save memory but you could
put a value in if it made sense.
If you got items in a list, you can assign them to a hash
slice in one go like this:
my @items = qw(foo bar etc);
my %checklist;
@checklist{@items} = (undef) x @items;
The (value) x n construct evaluates to a list of n occurences
of value.
Regards
Grant
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> -----Original Message-----
> From: Roland Corbet [mailto:[EMAIL PROTECTED]]
> Sent: Friday, February 02, 2001 4:01 AM
> To: [EMAIL PROTECTED]
> Subject: Quick Way to see if an item is in a list
>
>
>
> Currently, I have:
>
> @mylsit = ("foo", "bar", "etc.");
> $MATCHED = 0;
>
> foreach $VAR (@mylist) {
> if ($VAR =~ m/what I want to match/i) {
> $MATCHED = 1;
> }
> }
>
> if ($MATCHED == 1) {
> print "Matched";
> #do matched code here
> }
> else {
> print "No match";
> #do no match code here
> }
>
> but I was wondering if there was a RegEx trick/method to
> compare to each
> element in a list. At the end of the day, what I want to do
> is check if a
> filename (stored in a variable) has an extension that is one
> of those in a
> valid list of extensions.
>
> Any ideas, help or advice would be appreciated.
>
> TIA
>
> Roland
>
>
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