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Scalar function

by gon770 (Novice)
on Sep 07, 2012 at 16:52 UTC ( #992345=perlquestion: print w/ replies, xml ) Need Help??
gon770 has asked for the wisdom of the Perl Monks concerning the following question:

Hello, PerlMonks.

I am having trouble with new lines (\n). It seems like everything within scalar will print new line. For instance,

$_ and $fa
$fb
$fc

But, I want it to be $_ $fa $fb $fc in same line.
Should I try different function? Or there is an optional augument for scalar function? Thank you

while(<$fi>){ chomp; print CSV $_, scalar <$fa>, scalar <$fb>, scalar <$fc>; }

Comment on Scalar function
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Re: Scalar function
by philiprbrenan (Monk) on Sep 07, 2012 at 16:57 UTC
Re: Scalar function
by MidLifeXis (Prior) on Sep 07, 2012 at 17:11 UTC

    If $fa, $fb, and $fc are file handles, then

    print CSV $_, scalar <$fa>, scalar <$fb>, scalar <$fc>;
    is doing the equivalent of
    my $line_a = <$fa>; my $line_b = <$fb>; my $line_c = <$fc>; print CSV $_, $line_a, $line_b, $line_c;
    Note that there is no chomp on the reads from the three files.

    --MidLifeXis

Re: Scalar function
by johngg (Abbot) on Sep 07, 2012 at 22:45 UTC

    As MidLifeXis points out, you need to chomp your newlines.

    $ perl -E ' > open my $fa, q{<}, \ <<EOF1 or die $!; > file A line 1 > file A line 2 > EOF1 > > open my $fb, q{<}, \ <<EOF2 or die $!; > file B line 1 > file B line 2 > EOF2 > > say join q{,}, > map { chomp; $_ } scalar <$fa>, scalar <$fb>;' file A line 1,file B line 1 $

    I hope this is helpful.

    Update: A more complete example putting the $fa, $fb and $fc filehandles in an array and showing how you might cope if they contain fewer lines than $fi using eof.

    $ perl -Mstrict -Mwarnings -E ' > open my $fi, q{<}, \ <<EOFi or die $!; > File I Line 1 > File I Line 2 > File I line 3 > EOFi > > open my $fa, q{<}, \ <<EOFa or die $!; > File A Line 1 > File A Line 2 > EOFa > > open my $fb, q{<}, \ <<EOFb or die $!; > File B Line 1 > File B Line 2 > File B Line 3 > EOFb > > open my $fc, q{<}, \ <<EOFc or die $!; > File C Line 1 > File C Line 2 > File C Line 3 > File C Line 4 > EOFc > > my @slaveFHs = ( $fa, $fb, $fc ); > while ( <$fi> ) > { > chomp; > say join q{,}, $_, > map { chomp; $_ } > map { eof $_ ? q{--eof--} : scalar <$_> } > @slaveFHs; > }' File I Line 1,File A Line 1,File B Line 1,File C Line 1 File I Line 2,File A Line 2,File B Line 2,File C Line 2 File I line 3,--eof--,File B Line 3,File C Line 3

    Cheers,

    JohnGG

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