Beefy Boxes and Bandwidth Generously Provided by pair Networks
P is for Practical
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
So, trying to put this together: It appears the combination of assigning the text to the variable ("$strings = <FILE>"), followed by the script, continuing to run (via the infinite loop), that can re-use the contents of $strings as many times as required, is the essence of the mechanism to avoid re-reading the file...

Not really. For one thing you have a mistake (repeated twice) which may be a typo but which is also substantial, so I'm pointing it out: it's not $strings, but @strings! The difference is that the former on the lhs of an assignment imposes scalar context. Thus $strings = <FILE> puts into $strings a single "line". Now, I write "line" in double quotes because it may even be the whole file, as a single string, depending on the input record separator ($/ - look it up in perldoc perlvar). For simplity let's assume that the latter has not been changed from the default and that lines are actually lines: when you do @strings = <FILE> you're in list context instead and each element of the @strings array is a line. Then you iterate over it as over any other list. That's it.

Let's move on: perhaps a bigger and more severe misunderstanding on your part is with the infinite loop: that has nothing to do with looping over @strings, it is orthogonal. Indeed the latter is nested in the former: here you have two loops one within the other, the second of which disguised as a grep.

In all earnestness, I'm not familiar with the Llama book, but if this is its final exercise I must presume you've gone through all of it and please don't take it as a personal offense, but I find it a bit surprising that you're still doing all this confusion...


In reply to Re^3: Don't re-read file for each new pattern... by blazar
in thread Don't re-read file for each new pattern... by cgmd

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!
  • 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, 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, 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.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others examining the Monastery: (9)
    As of 2015-07-05 17:35 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









      Results (67 votes), past polls