On Mar 21, Jonathan E. Paton said:
>> I have a one big text file and also I have some
>> set of strings to be replaced by another set of
>> strings. Currently, I am reading each line of
>> the file, and replacing one set of strings by
>> another set of strings, one after another. Is
>> there any efficient way of doing this? The data
>> is so huge that this job takes around 7Hrs of
>> total time on Sun Ultra 10.
>
>my $word = "WORD";
>
>while (<>) {
> s/$word/lie/g; #Slow
>}
>
>is slow because that $word forces the regex to
>be recompiled each time through. The best way
>to solve this problem is to create a Perl
>script on the fly and run using eval $script;
Not true about that regex. Here is a comparison:
for $w (@words) {
for (@lines) {
if (/$w/) { ... }
}
}
vs.
for (@lines) {
for $w (@words) {
if (/$w/) { ... }
}
}
The second can be much slower than the first.
--
Jeff "japhy" Pinyan [EMAIL PROTECTED] http://www.pobox.com/~japhy/
RPI Acacia brother #734 http://www.perlmonks.org/ http://www.cpan.org/
** Look for "Regular Expressions in Perl" published by Manning, in 2002 **
<stu> what does y/// stand for? <tenderpuss> why, yansliterate of course.
[ I'm looking for programming work. If you like my work, let me know. ]
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