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printf function alternative? formatting without printing

by fraizerangus (Sexton)
on Jan 09, 2010 at 15:21 UTC ( #816487=perlquestion: print w/ replies, xml ) Need Help??
fraizerangus has asked for the wisdom of the Perl Monks concerning the following question:

Hi Everyone Sorry for the rookie question but, I'm using
$n -= ($n * $u) * $u; printf "%d\n", abs($n);
iterating through to get a result I want, but I want to save this result in an index of an array, but the above function just prints it to the screen I can't do anything with it?! to save the result and process it further is there anyway I can format it and save it as a string, in a for loop? e.g.
array [$i] = (printf "%d\n", abs($n));
many thanks and apologies if this question seems or sounds stupid to you?

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Re: printf function alternative? formatting without printing
by CardinalNumber (Prior) on Jan 09, 2010 at 15:34 UTC
Re: printf function alternative? formatting without printing
by FunkyMonk (Canon) on Jan 09, 2010 at 16:16 UTC
    Generally speaking, Perl treats numbers and stringified numbers as equal (ie perl -e "print 'equal' if '6.0' == 6" will print "equal"). So int will do just as good a job as sprintf.
Re: printf function alternative? formatting without printing
by ww (Bishop) on Jan 09, 2010 at 18:41 UTC

    Both the advice from CardinalNumber and, even more so, the observation by FunkyMonk are clearly on target. In the hope of offering some additional clarity:

    printf produces output; sprintf merely formats

    However, I'm perplexed by your use of "string" in the phrase "save it as a string" as well as by some other aspects of the question. For example, do you mean that $n and $u are floating point numbers (assumed below) or can they be ints; a mixture; or something else??

    All the above leads me to send a question back: Does this come somewhere close to your intent?

    #!/usr/bin/perl use strict; use warnings; # 816487 my $n = 3.123; my $u = 3.678; my $i= 0; my (@array, $array); for (1..10) { $n -= ($n * $u) * $u; $array[$i] = int(abs($n)); $i++ } for (@array) { print "$_ \n"; }

    Output, for $n=3.123, $u=3.678

    39 490 6140 76922 963664 12072486 151240294 1894690621 23736085384 297358177092

    and for $n=3.123, $u=4.0

    46 702 10540 158101 2371528 35572921 533593828 8003907421 120058611328 1800879169921

    And another question: "Waaaay off? Helpful?" (I hope the latter.)

Re: printf function alternative? formatting without printing
by toolic (Chancellor) on Jan 09, 2010 at 18:43 UTC
Re: printf function alternative? formatting without printing
by mnooning (Sexton) on Jan 09, 2010 at 18:55 UTC
    Yes. sprintf FORMAT, LIST Just use sprintf instead of printf, and assign it to the array.
Re: printf function alternative? formatting without printing
by ikegami (Pope) on Jan 09, 2010 at 19:04 UTC
    If you're dealing with integers,
    $array[$i] = abs($n);

    If you're dealing with floats,

    use POSIX qw( ceil floor ); $array[$i] = int(abs($n)); # Truncates $array[$i] = sprintf('%d', abs($n)); # Rounds $array[$i] = ceil(abs($n)); # Finds ceiling $array[$i] = floor(abs($n)); # Finds floor

    Add the "\n" when you print. There's no reason to store it in the array.

Re: printf function alternative? formatting without printing
by ravi.s (Initiate) on Jan 09, 2010 at 21:19 UTC
    You might have to save the output and "push" those values into array instead of printing the value. Sample Code : <code>for ( condition ) { $n -= ($n * $u) * $u; push(@i,"$n"); }<code>

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