org chen wrote:
I have a huge file, there are 47,286,116 lines. I am search a line and
repalce this line with another string. I know this line is between
20,000,000th to 30,000,000th lines. Which way is more fast and safe:
method 1:
use Tie::FILE;
tie my @array, 'Tie""File', "aa.txt", memory =>100_000_000 or die;
for(my $i = 20000000; $i < 30000000; $i ++){
.......
}
untie @array;
method 2;
open(AA, "aa.txt");
while(<AA>){
...
}
close(AA);
20,000,000 is about at the middle of the file so start there first:
use Fcntl ':seek';
open my $AA, '<', 'aa.txt' or die "Cannot open 'aa.txt' $!";
seek $AA, ( -s $AA ) / 2, SEEK_SET or die "Cannot seek 'aa.txt' $!";
while ( <$AA> ) {
...
}
close $AA;
John
--
Perl isn't a toolbox, but a small machine shop where you
can special-order certain sorts of tools at low cost and
in short order. -- Larry Wall
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