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Re: Possible to refer to variable defined later in script?

by Athanasius (Chancellor)
on Nov 12, 2012 at 16:35 UTC ( #1003477=note: print w/replies, xml ) Need Help??


in reply to Possible to refer to variable defined later in script?

It is possible to read the filehandle’s position immediately before printing the empty (zero) value, and then later to return to this position in the file and overtype the zero value with the correct one. But this requires the file to be opened for writing rather than appending:

open(my $HTML, '>', 'OUT-access.html') or die "Cannot open file 'OUT-a +ccess.html' for writing: $!"; ... print $HTML "There were "; my $offset = tell $HTML; printf $HTML "%7d", 0; print $HTML " unique visitors in the logfile.<BR>\n"; ... # Calculate $IPcount; ... seek $HTML, $offset, 0; printf $HTML "%7d", $IPcount;

(The value of “7” in the format "%7d" assumes that the count will have at most 7 digits. Choose whatever number is appropriate for your use-case.)

See tell and seek.

Athanasius <°(((><contra mundum

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[1nickt]: james28909 You lost me a bit when you said "show me evolution from intelligence to ignorance". I guess we would have to define the terms, but as I look around at my species and how we are destroying our habitat ...
[james28909]: seems like a person cant even have a belief without hurting someones feelings. i never said my way is the only way. i just said i have pretty good scientific evidence, and then asked for opposing side to present evidence
[james28909]: was downvoted and left without a reply. go figure
[holli]: but then you DO give a fuck
[1nickt]: I don;t think beliefs should be down-voted, just behaviours.
[james28909]: im not quite how to explain it any better nick. you evolved from ignorance to intelligence. not the other way. the universe evolves from gas coulds and debris into planets stars and galaxies ect. it doesnt happen any other way. hence it has ....
[james28909]: some kind of logic behind it
[james28909]: and that is also anothe rpoint i made, i think it has to do with perception of the world around you. most people think of evolution on a human scale. why could life evolve on this planet? because this planet evolved in this solar system. and so on.
[holli]: here's something for you to watch, James. I think you will like it
[erix]: for the record: I have not downvoted anyone on that subthread that was my fault

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