James Edward Gray II wrote: > > On Jan 2, 2004, at 10:46 AM, Ed Christian wrote: > > > James Edward Gray II wrote: > >> On Jan 2, 2004, at 10:10 AM, Paul Kraus wrote: > >> > >>>> Don't do that. The foreach reads the whole file into memory and > >>>> then walks it line by line. If we just want one at a time, let's > >>>> fetch them that way > >>> > >>> I don't agree with this. > >> > >> And I don't understand this. ;) > >> > >>> If you are working with a file that is as small as > >>> the one included seems to be easier to just load up some data > >>> structures. I understand writing efficient code is always best but > >>> for a quickie script like this I wouldn't be to concerned with the > >>> 1/100th of a ms that your going to shave off but not dumping the > >>> contents to memory. > >> > >> If you're going to work with the lines one at a time anyway, what > >> exactly is the advantage of using the probably slower and definitely > >> more memory wasteful foreach()? > > > > While the foreach is certainly more wasteful, why in the world would > > you > > re-initialize and re-open the file multiple times? Why not just open > > the > > file once and iterate over the file, comparing each line of the file to > > each of the keys in the %input hash? > > Your way is certainly better, if output order doesn't matter. The > original code checked the first key against the file, then second, then > third. Your suggestion could find the sixth index before it finds the > first. If the order doesn't matter though, I agree that your > suggestion would be boatloads more efficient.
Except that there's no need to reopen the file. A simple seek DATA, 0, 0 will do the trick with very little overhead. Rob -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
