Ankur Gupta wrote:
[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> wrote:
Hey Guys
I am having an odd problem using grep to ensure an array only
contains distinct entries.
I have a list similar to the following in a file (short example of a
much longer list)
support01-FastEthernet1/0
support01-RH
jnormandin-p370-1691-SH-Cpu-2
jnormandin-p370-1691-SH
These entries may or may not appear multiple times within that list.
I am trying to create an ARRAY containing each of these entries only
once (a distinct list). I am using a grep statement:
push @pingErrorsName, $element if (! grep (/\b$element\b/,
@pingErrorsName));
push @pingErrorsName, $element if ( ! grep { $_ eq $element }
@pingErrorsName );
or
push @pingErrorsName, $element if ( ! grep { /^$element$/ }
@pingErrorsName );
should work.. (untested though).
But this would be inefficient for large arrays.
Use hash instead.
$pingErrorsName{$element} = undef;
Retrieve the elements by
@elements = (keys %pingErrorsName);
This loses the sort order, if you care.
foreach $element....
{
next if exists $hash{$element};
--OR--
next if grep( /$element/, @array);
push @array, $element;
$hash{element} = 1;
}
undef %hash; # house cleaning
I suspect that the grep approach slows down with larger arrays while the
%hash approach is a memory hog...
This is also one of those times where the use of 'o' in your regex
/$element/o would be VERY VERY bad... :)
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