Let me elaborate: 
if ($student = "") {print "Cannot find that student, try again\n";}

[download]
Says, essentially, if the result of assigning the value "" to $student is true....

The problem with that? $student = "" both returns a false value AND makes $student contain an empty string!

The comparison operators are == for binary values (numbers, mostly) and eq for strings. What you really want is: 

if ($student eq "") {print "Cannot find that student, try again\n";}

## OR, Better

unless ($student) {print "Cannot find that student, try again\n";}

[download]
That way, $student will still hold the value you expect when you reach your print statement. If you use the latter version, it will also function properly if $student is undefined for some reason ("" and undefined are slightly different, but both false).

It's a very common mistake, and hard to catch. The above advice to use strict; and use warnings; is sound. Also, learning to use the perl debugger might have helped you here.

radiantmatrix
require General::Disclaimer;

In reply to Re^2: Printing two variables in the same line by radiantmatrix
in thread Printing two variables in the same line by JustLikeThat

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.