Re^2: blank lines up to a point

The flip-flop use is interesting. I would have done:

my $line;
do {
   $line = <DATA>;
} until ($line=~m/\S/);

do {
   s/\0//g;
   print $line;
} while($line=<DATA>);

__DATA__



Some text

More text
And so one

and on...
[download]

It's one less operation per iteration of the second loop, which would be ever-so-slightly faster on large files (I think).

^{--

$me = rand($hacker{perl});}

Comment on Re^2: blank lines up to a point Download Code

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Re^3: blank lines up to a point by Random_Walk (Prior) on Sep 16, 2004 at 09:13 UTC
I think the reason I used the flip flop was so the subroutine held state as the OP was asking for a subroutine to provide this behaviour when being passed one line at a time (and because it was a bit fun). Your method does look faster for large files (and probably any size files) but I think you are cheeting a bit by using execution flow to hold state. I propose a less interesting subroutine that is probably as fast as yours. Once $flipped is set there is only one check made in each sub call due to short circuiting the rest of the `or` when the first side is true. `#!/usr/local/bin/perl -w use strict; my $flipped=0; sub logit { my $line=shift; $line=~s/\0//g; return unless ($flipped or ($line=~/\S/ and ++$flipped)); print $line; } while (<DATA>) {&logit ($_)} __DATA__ we dont really need this again but here it is anyway` [download] Cheers, R.	[reply] [d/l] [select]

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Re^3: blank lines up to a point
by Random_Walk (Prior) on Sep 16, 2004 at 09:13 UTC

I think the reason I used the flip flop was so the subroutine held state as the OP was asking for a subroutine to provide this behaviour when being passed one line at a time (and because it was a bit fun). Your method does look faster for large files (and probably any size files) but I think you are cheeting a bit by using execution flow to hold state.

I propose a less interesting subroutine that is probably as fast as yours. Once $flipped is set there is only one check made in each sub call due to short circuiting the rest of the or when the first side is true.

#!/usr/local/bin/perl -w
use strict;

my $flipped=0;
sub logit {
    my $line=shift;
    $line=~s/\0//g;
    return unless ($flipped or ($line=~/\S/ and ++$flipped));
    print $line;
}

while (<DATA>) {&logit ($_)}
__DATA__

we dont really need this again

but here it is anyway
[download]

Cheers,
R.

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