RE: newbie - in
check out "perldoc -f grep" -Original Message- From: Kyle Babich [mailto:[EMAIL PROTECTED]] Sent: Friday, September 27, 2002 4:34 AM To: beginners Subject: newbie - in Does Perl have an in operator or something similar? If not how would I find out if a certain list has a certain element? Thank you, -- Kyle -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: newbie - in
On Fri, 27 Sep 2002, Kyle Babich wrote: > Does Perl have an in operator or something similar? > If not how would I find out if a certain list has a certain element? Read through perldoc -q 'How can I tell whether a certain element is contained in a list or array?' -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: newbie - in
On Fri, 27 Sep 2002, Timothy Johnson wrote: > > check out "perldoc -f grep" grep should not be used for this purpose, it will run through the entire list even after the desired element has been found. > > -Original Message- > From: Kyle Babich [mailto:[EMAIL PROTECTED]] > Sent: Friday, September 27, 2002 4:34 AM > To: beginners > Subject: newbie - in > > > Does Perl have an in operator or something similar? > If not how would I find out if a certain list has a certain element? > > Thank you, > -- > Kyle > > -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: newbie - in
Kyle Babich wrote:
> Does Perl have an in operator or something similar?
> If not how would I find out if a certain list has a certain element?
>
> Thank you,
> --
> Kyle
simply loop through the list or array you have and see if you can find what
you are looking for:
my @i = ( 1..100 );
my $found = 0;
#-- looking for 34
foreach my $j (@i){
#-- exit as soon as possible
$found = 1, last if($j == 34);
}
print $found ? "found 34\n" : "34 not found\n";
or use a hash for faster loop up:
my %h;
my @i = ( 1..100);
@h{@i} = ();
if(exists $h{34}){
print "found 34\n";
}else{
print "34 not found\n";
}
don't use hash if:
1. @i has duplicate value which you want to keep
2. order is important
3. @i is huge and takes up a lot of memory
david
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
RE: newbie - in
And who would care if the list always remains small enough that it wouldn't make a difference? use grep, if you notice a performance issue at that command then it's time to think of other methods of doing your operation (hint hashes). Personally I avoid making giant arrays, heck I aviod too much data in memory all together, but once you have to have too much data in memory you already have a problem that you should be re-thinking to use less of it. > -Original Message- > From: Sudarshan Raghavan [mailto:[EMAIL PROTECTED]] > Sent: Sunday, September 29, 2002 4:01 AM > To: Perl beginners > Subject: RE: newbie - in > > > On Fri, 27 Sep 2002, Timothy Johnson wrote: > > > > > check out "perldoc -f grep" > > grep should not be used for this purpose, it will run through > the entire > list even after the desired element has been found. > > > The views and opinions expressed in this email message are the sender's own, and do not necessarily represent the views and opinions of Summit Systems Inc. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
