Beloved Monks,

I seek your wisdom re why the 4th one-liner below returns "Matches!".  The other 7 one-liners behave as I would have expected.  I thought $a.$b would be the same as "$a$b" in contexts like this - it seems to be with last 'eq' tests.  Was I mistaken?  If I print them the output looks the same. 

$ perl -e '$a="A";$b="B";print "Matches!\n" if "$a$b" =~ /A/'
Matches!

$ perl -e '$a="A";$b="B";print "Matches!\n" if "$a$b" =~ /C/'

$ perl -e '$a="A";$b="B";print "Matches!\n" if $a.$b =~ /A/'
Matches!

$ perl -e '$a="A";$b="B";print "Matches!\n" if $a.$b =~ /C/'
Matches!    # WHY???


$ perl -e '$a="A";$b="B";print "Matches!\n" if "$a$b" eq "AB"'
Matches!

$ perl -e '$a="A";$b="B";print "Matches!\n" if "$a$b" eq "C"'

$ perl -e '$a="A";$b="B";print "Matches!\n" if $a.$b eq "AB"'
Matches!

$ perl -e '$a="A";$b="B";print "Matches!\n" if $a.$b eq "C"'

[download]
I added blank lines above purely for readability.
I'm running Perl 5.16.3 on Linux.
Thanks.
tel2

In reply to Why is $a.$b not = "$a$b"? by tel2

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.