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  47                      <div class="entry" id="entry-516">
  48                         <h3 class="entry-header">Perl test</h3>
  49                         <div class="entry-content">
  50                            <div class="entry-body">
  51                               <ul>
  52   <li>Ray wanted an easy/medium/hard Perl test</li>
  53 </ul>
  54                            </div>
  55                            <div id="more" class="entry-more">
  56                               <h2>Perl Test</h2>
  57
  58 <h3>Easy</h3>
  59 <ol>
  60   <li>What does Perl stand for?</li>
  61
  62 <p><font color="red">Practical Extraction and Reporting Language</font></p>
  63
  64   <li>What basic datatypes does Perl support?</li>
  65
  66 <p><font color="red">Scalar, Array, Hash, Typeglob</font></p>
  67
  68   <li>What does the following do:</li>
  69
  70 <div class="code"><pre>
  71 my @output = &lt;STDIN&gt;;
  72
  73 foreach (@output) {
  74   print "$_\n" if /\d+/;
  75 }
  76 </pre></div>
  77
  78 <p><font color="red">Echoes lines that have numbers in them)</font></p>
  79
  80 </ol>
  81
  82 <h3>Medium</h3>
  83
  84 <ol>
  85   <li>What is <tt>use strict</tt> and why is it important to use?</li>
  86
  87 <p><font color="red">Strict requires that variable references are scoped - e.g. my $var)</font></p>
  88
  89   <li>What does the following code do:</li>
  90
  91 <div class="code"><pre>
  92 sub d {
  93   my %p = @_;
  94
  95   print "\np:\n";
  96
  97   foreach (sort (keys (%p))) {
  98     if (/password/) {
  99       print "$_: &lt;password&gt;\n";
 100     } else {
 101       print "$_: ${p {$_}}\n";
 102     } # if
 103   } # foreach
 104 } # d
 105 </pre></div>
 106
 107 <p><font color="red">Displays the contents of the passed in hash %p substituting "&lt;password&gt;" if the hash happens to have a key of password</font></p>
 108
 109   <li>What do you do to enable Perl to find user written modules?</li>
 110
 111 <p><font color="red">You need to modify the @INC array to include the path to your modules)</font></p>
 112 </ol>
 113
 114 <h3>Hard</h3>
 115
 116 <ol>
 117   <li>What is the difference between <tt>require</tt> and <tt>use</tt>?</li>
 118
 119 <p><font color="red">See <a href="/blogs/Status/archives/000492.html">this article</a> for the answer</font></p>
 120
 121   <li>What is a better way to do the following and why:</li>
 122
 123 <div class="code"><pre>
 124 undef $/;
 125 </pre></div>
 126
 127 <p><font color="red">See <a href="/blogs/Status/archives/000492.html">this article</a>) for the answer</font></p>
 128
 129   <li>What does the following print out when executed:</li>
 130
 131 <div class="code"><pre>
 132 sub foo {
 133   my ($x, $y) = @_;
 134
 135   my @z = `$x 2&gt;&amp;1`; chomp @z;
 136   my $s = $?;
 137
 138   if ($s ne 0) {
 139     if (defined $y) {
 140       print "$_\n" foreach (@z);
 141     }
 142   }
 143
 144   return ($y, @z);
 145 } # foo
 146
 147 my @a;
 148 my $c="ls /temp";
 149 my $d;
 150
 151 ($d, @a) = foo $c;
 152 print "Worked!\n" if !$d;
 153 </pre></div>
 154
 155 <p><font color="red">(It will output:</p>
 156
 157 <div class="code"><pre>
 158 Worked!
 159 </pre></div>
 160
 161 <p>Yet nothing really worked at all! Key issues are:</p>
 162
 163 <ul>
 164     <li>Passing parameters to subroutines. Two parameters are passed in</li>
 165
 166     <li>Parameter return: Two parameters are returned</li>
 167
 168     <li>Evaluation of parameters: $y in foo is not passed in thus the print... foreach doesn't execute></li>
 169
 170     <li>Evaluation of true/false: foo returns $y which is errno,
 171 which is not 0 thus not true but the !$d evaluates to true and the
 172 print "Worked!\n" gets executed.</li>
 173 </font></ul>
 174 </ol>
 175
 176                            </div>
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 178                         <p class="entry-footer">
 179                            <span class="post-footers">Posted by  on January 13, 2006 11:59 AM</span> <span class="separator">|</span> <a class="permalink" href="http://defaria.com/blogs/Status/archives/000516.html">Permalink</a>
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