Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl Monk, Perl Meditation
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
my @lines = <DNAFILE>; while (<DNAFILE>) { say $_; }
This piece of code doesn't make sense. First, you read the *whole* file into memory (storing it at @lines), and then you try to read another line (your while loop), which is, of course, not possible. Your loop won't be executed; you can remove it without harm.

But the main problem is that you read the whole file into memory and process it from there. No wonder that your memory gets exhausted sooner or later (try to pour a whole bottle of beer into a coffee cup; unless the cup is really huge, you will spill some beer). Maybe Tie::File will help you as a first start. It allows you to treat the whole file as an array, without slurping it into memory. Be aware that, possibly, the runtime of your application will increase.

-- 
Ronald Fischer <ynnor@mm.st>

In reply to Re: Request to detect the mistake in a perl script for finding inter-substring distance from a large text file by rovf
in thread Request to detect the mistake in a perl script for finding inter-substring distance from a large text file by supriyoch_2008

Title:
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 or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

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

How do I use this? | Other CB clients
Other Users?
Others surveying the Monastery: (5)
As of 2022-08-14 06:09 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found

    Notices?