Re: question regarding slices


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Re: question regarding slices

by tcf22 (Priest)

on Nov 06, 2003 at 18:44 UTC ( [id://305114]=note: print w/replies, xml )

Need Help??

in reply to question regarding slices

You could use grep, like this

foreach(grep ! /^\.{1,2}$/, readdir(PRINT)){
    #do work
}
[download]

but it loops through the list twice, which may be a little inefficient, so you could use glob which removes the . and .. automatically.

my $dir = '/path/to/dir';
foreach(glob('$dir/*')){
    #do work
}
[download]

I prefer using glob().

As for retrieving all but the first 2 elements of the list, it is a little akward, so you could assign them into an array and do this

my @array = readdir(PRINT);
foreach(@array[2..$#array]){
  #do work
}
[download]

- Tom

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Re:x2 question regarding slices (don't use regexps to filter . and ..)
by grinder (Bishop) on Nov 06, 2003 at 21:54 UTC

Don't use grep to filter out these entries. Unless you know what you are doing, you open yourself to security problems (missing a directory you should traverse). And if you do know what you are doing, it looks strange to someone who doesn't, and so they might want to "fix" it and hence break it.

More discussion about this issue can be found at:

special directory entries (where blakem talks about subtle regexp issues).
Is readdir ever deterministic? (where merlyn explains in more detail how . and .. might move around).

And in case the OP isn't aware of them, this might be the right moment to mention File::Find and File::Find::Rule.

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