LanX is right about $" being a standard variable and global. He is also right that its default value must have been changed somewhere (possibly in a module you use) to undef to raise the warning you are seeing.

You can "fix" the value of $" by:

local $" = ' ';

open ...

[download]

which restores the default space used for $".

If you recently added use warnings to your script that would show a warning for a nasty condition that you previously weren't aware of. An array interpolated into as string behaves like:

my $arrayStr = join $", @{$table_A[$d]};
my $row1 = "$arrayStr";

[download]

so the undef value in $" would have turned into an empty string and the array elements would have been stuck together instead of separated by single spaces.

Perl is the programming world's equivalent of English

In reply to Re: Why do I get this error? by GrandFather
in thread Why do I get this error? by Anonymous Monk

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.