Per OP Update: I have an array Say, @array1 = qw (1,1,1,2,3,4,4,4,5,6,1,1,1,1,...). From this array i have to extract an output as "1,1,1,2,3,4,4,4,5,6,1" (i.e. to remove the X-number of 1's with just 1).

One way: 

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @ra = (1, 1, 1, 2, 3, 4, 4, 4, 5, 6, 1, 1, 1);
 dd \@ra;
 ;;
 my $one;
 $one = pop @ra while $ra[-1] == 1;
 push @ra, $one if defined $one;
 dd \@ra;
"
[1, 1, 1 .. 4, 4, 4, 5, 6, 1, 1, 1]

[1, 1, 1 .. 4, 4, 4, 5, 6, 1]

[download]

Update: Another way: 

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @ra = (1, 1, 1, 2, 3, 4, 4, 4, 5, 6, 1, 1, 1);
 dd \@ra;
 ;;
 my $highest;
 for my $i (reverse 0 .. $#ra) {
   last if $ra[$i] != 1;
   $highest = $i;
   }
 $#ra = $highest if defined $highest;
 dd \@ra;
"
[1, 1, 1 .. 4, 4, 4, 5, 6, 1, 1, 1]

[1, 1, 1 .. 4, 4, 4, 5, 6, 1]

[download]

Upon reflection, I think the second approach is better: it's more flexible. If one wanted to trim all but one undef value from the end of an array, one need only change the test within the for-loop from
    last if $ra[$i] != 1;
to
    last if defined $ra[$i];
and the job's done. The first approach does not have this flexibility.

Give a man a fish:  <%-(-(-(-<

In reply to Re: Read And modify a series by AnomalousMonk
in thread Read And modify a series by DarshanS

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.