Removing an element from array 1

[perln00b]

Support I have two arrays, and each of them doesn't have repeat elements. And compare the first array to the second one, if element repeats in 2nd array, the element has to be removed from the 1st one. i.e.
###################################################
@arry1 = ("1", "2", "3");
@arry2 = ("9", "10", "1");
###################################################

So, "1" is the common element for both arrays, but I only need to remove it from the 1st array.

Does anyone have any idea to handle this?

Thanks,
Lucas

 

[Corwinsw]

definitely better

Corwin

 

[rharsh]

Not much different, only it doesn't use a temporary array:

my @a1 = qw(1 R 3 5 7 9 X 12 2 W 3);
my @a2 = qw(2 5 4 9 1 X);
my %a2_hash = map {$_,1} @a2;
@a1 = grep {! defined $a2_hash{$_}} @a1;
print "@a1";

Since splice was used in a couple of the examples, and this might be a bit easier to understand for the newer guys (or maybe not?), here's a different way to go about it:

my %a2_hash;
foreach (@a2) {
    $a2_hash{$_}=1;
}

for (my $i=0; $i <= $#a1; $i++) {
    if (exists $a2_hash{$a1[$i]}) {
        splice(@a1, $i, 1);
        redo; # Doesn't increment $i
    }
}

print "@a1";[/code]

 

[duncdude]

Hi rharsh

You are right - it is a crap solution!


Kind Regards
Duncan

 

[orangegal]

pop would do, i think

 

[KevinADC]

orangegal,

if you have this:

@arry1 = ("1", "2", "3");
@arry2 = ("9", "10", "1");

and want to get rid of the duplicate (1) you could pop @arry2, but thats only going to work if you know the order and the values of both arrays beforehand. The above example is not going to be the real data though.