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

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
Enlightened Ones,

I downloaded a (huge) number of webpages from the internet using a perl routine some time ago. Now I want to check if there are any files that I missed or that are new.

It is actually more complicated than this (as I have to retrieve information from a database first, open up webpages and then extract bits and pieces from the resulting pages). What it boils down to, however, is that I have a list of the files on my computer and that I can generate a list of the webpages. I can link these two by a common piece of information (there is an ID-number on the webpages, which I use to construct the file name). Now the question is, how do I create a third list that gives me all the webpages that my new search of the database returned but which I haven't downloaded yet (i.e., are not contained in the list of files). How can I compare the elements in two lists with a view to elements that are contained in one but not the other.

Go with Perl!

Many Thanks in advance!

In reply to Checking for new files by New Novice

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?

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

How do I use this? | Other CB clients
Other Users?
Others avoiding work at the Monastery: (1)
As of 2023-01-29 21:33 GMT
Find Nodes?
    Voting Booth?

    No recent polls found