Beefy Boxes and Bandwidth Generously Provided by pair Networks
more useful options
 
PerlMonks  

Re: Perl Best Practices book: is this one a best practice or a dodgy practice?

by TedPride (Priest)
on Sep 03, 2005 at 10:17 UTC ( #488893=note: print w/ replies, xml ) Need Help??


in reply to Perl Best Practices book: is this one a best practice or a dodgy practice?

Mmm. The only reason to read the original file line by line would be that it's very large, meaning that data processing time is likely to be significant, meaning in turn that there's an increased risk of the process being interrupted. Given that the process may be interrupted, your script can't be designed so that an interruption loses you large chunks of data. I would agree that in this instance, it's necessary to create a temporary file.


Comment on Re: Perl Best Practices book: is this one a best practice or a dodgy practice?
Re^2: Perl Best Practices book: is this one a best practice or a dodgy practice?
by TheDamian (Priest) on Sep 03, 2005 at 21:45 UTC
    The only reason to read the original file line by line would be that it's very large...
    Surely not the "only" reason. Here are five other possible reasons, just off the top of my head. You might use a line-by-line approach:
    • to allow the application to be used interactively
    • to allow the application to be used as part of an unbuffered pipeline
    • to minimize memory usage even on small inputs, in an embedded (or otherwise memory-limited) environment
    • to restrict the tranformation to transforming individual lines (perhaps for backwards compatibility with a previous utility)
    • Because the input data is always runtime-generated (or highly volatile in some other way), so rerunnability doesn't matter
    Note that I don't disagree with you that using temporary files is safer in general, if you can afford the costs involved. After all, using temporary files is precisely what IO::Insitu does. I only question your argument that its possible to deduce the necessity for temporary files from the particular I/O characteristics of the original example (or from any piece of undocumented code for that matter).

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://488893]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others making s'mores by the fire in the courtyard of the Monastery: (9)
As of 2014-07-29 21:07 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    My favorite superfluous repetitious redundant duplicative phrase is:









    Results (228 votes), past polls