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Re: processing a file once within a nest for loop

by Speedy (Monk)
on Feb 15, 2002 at 23:03 UTC ( [id://145784]=note: print w/replies, xml ) Need Help??


in reply to processing a file once within a nest for loop

You are right about having to protect the values in @tmpl. Once you change the word DOMAIN to the first @subs value, in your original code you have changed your template itself and can no longer substitute for DOMAIN -- in your case you now need to substitute for "itchy.foo"

Try this sample code, where I substituted for the $j variable name something a bit more descriptive, and before each potential replacement saved each template string to a new "str_for_subbing" (and made up an "input" for the template file so I could see some real output).

#!/usr/bin/perl use strict; my @subs = qw(itchy.foo scratchy.bar homer.bab); my @tmpl = ("To: webmaster\@DOMAIN", "Dear Sir or Madam:", "You have +won \$1,000,000!"); my ($sub, $str, $str_for_subbing); for $sub(@subs) { open(FH,">virt.$sub") or die; # Assume @templ in your code should have been @tmpl # -- good reason to use strict! foreach $str (@tmpl) { $str_for_subbing = $str; $str_for_subbing =~ s/DOMAIN/$sub/g; print "$str_for_subbing\n"; print FH "$str_for_subbing\n"; } close(FH) }

If you don't assign each $str to a $str_for_subbing, you do change the value of $str in the template on the first substitution for DOMAIN, which was not your intent. Substituting in a "copy" of each string saves you this grief.

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