If Todd wants to print lines containing "Line 1", "Line 3", and "Line 7",
he's going to have to correct for zero-indexing:
user@book:~$ raku -e '$*IN.lines[ 1,3,7 ].join("\n").put;' < Lines.txt
Line 2
Line 4
Line 8
#Below: subtracting one from (1,3,7) gives the return he wants:
user@book:~$ raku -e '$*IN.lines[ (1,3,7).map: { $_ - 1 }
].join("\n").put;' < Lines.txt
Line 1
Line 3
Line 7
Now, does anyone have a simpler way than using the ".map" above?
HTH, Bill.
On Tue, Aug 25, 2020 at 10:46 AM Andy Bach <andy_b...@wiwb.uscourts.gov>
wrote:
> Ah, I see, the -n reads a line and then my lines on $*IN starts with the
> next one
> C:\> type lines.txt | "\Program Files (x86)\rakudo\bin\raku.exe" -e "my
> @x = $*IN.lines(); say @x[0,1,7,3]; "
> (Line 0 Line 1 Line 7 Line 3)
>
> and so $*IN is the default for lines()
> C:\> type lines.txt | "\Program Files (x86)\rakudo\bin\raku.exe" -e "my
> @x = lines(); say @x[0,1,7,3]; "
> (Line 0 Line 1 Line 7 Line 3)
>
> This hangs, with and without the -n
> C:\> "\Program Files (x86)\rakudo\bin\raku.exe" -ne "my @x =
> $*IN.lines(); say @x[0,1,7,3]; " lines.txt
>
> Though:
> C:\> "\Program Files (x86)\rakudo\bin\raku.exe" -ne "my @x = lines();
> say @x[0,1,7,3]; " lines.txt
> (Line 1 Line 2 Line 8 Line 4)
> Cannot do 'get' on a handle in binary mode
> in block <unit> at -e line 1
>
> a
>
> Andy Bach, BS, MSCMECFA
> Systems Mangler
> Internet: andy_b...@wiwb.uscourts.gov
> Voice: (608) 261-5738, Cell: (608) 658-1890
>
> "The three great problems of computer science:
> compiler complexity and 'off-by-one' errors".
> https://martinfowler.com/bliki/TwoHardThings.html
>
> ------------------------------
> *From:* Andy Bach <andy_b...@wiwb.uscourts.gov>
> *Sent:* Tuesday, August 25, 2020 12:18 PM
> *To:* Parrot Raiser <1parr...@gmail.com>
> *Cc:* perl6-users <perl6-us...@perl.org>; ToddAndMargo <
> toddandma...@zoho.com>
> *Subject:* Re: print particular lines question
>
> On Win10
> C:\>type lines.txt | "\Program Files (x86)\rakudo\bin\raku.exe" -ne "say
> lines()[1,7,3]; "
> (Line 2 Line 8 Line 4)
> (Line 11 Nil Nil)
>
> C:\>type lines.txt | "\Program Files (x86)\rakudo\bin\raku.exe" -ne "say
> lines()[1,7,3].join(qq~\n~); "
> Line 2
> Line 8
> Line 4
> Use of Nil in string context
> in block at -e line 1
> Use of Nil in string context
> in block at -e line 1
> Line 11
>
> and, speaking of that off by one problem ... lines.txt does start with
> "line 0"
> C:\> type lines.txt | "\Program Files (x86)\rakudo\bin\raku.exe" -ne "my
> @x = $*IN.lines(); say @x[0,1,7,3]; "
> (Line 1 Line 2 Line 8 Line 4)
>
> a
>
> Andy Bach, BS, MSCMECFA
> Systems Mangler
> Internet: andy_b...@wiwb.uscourts.gov
> Voice: (608) 261-5738, Cell: (608) 658-1890
>
> "The three great problems of computer science:
> compiler complexity and 'off-by-one' errors".
> https://martinfowler.com/bliki/TwoHardThings.html
>
> ------------------------------
> *From:* Parrot Raiser <1parr...@gmail.com>
> *Sent:* Tuesday, August 25, 2020 11:22 AM
> *To:* Andy Bach <andy_b...@wiwb.uscourts.gov>
> *Cc:* perl6-users <perl6-us...@perl.org>; ToddAndMargo <
> toddandma...@zoho.com>
> *Subject:* Re: print particular lines question
>
> That will golf a little (and improve it) to:
>
> $ raku -e '.say for lines()[3,2,5]' lines.txt
>
> but you have to remember that it's zero-based. I used the first sample
> file and got
> Line 4
> Line 3
> Line 6
>
> "The three great problems of computer science: compiler complexity and
> 'off-by-one' errors".
>
>
> On 8/25/20, Andy Bach <andy_b...@wiwb.uscourts.gov> wrote:
> >> Assigning `my @x=$_.lines` puts everything into $x[0]
> >
> > Trying this on windows
> >
> > C:\> raku.exe -e "my @x = 'lines.txt'.IO.lines; say
> > @x[1,7,3].join(qq~\n~); "
> > Line 1
> > Line 7
> > Line 3
> >
> > or
> > C:\> raku.exe -e " say 'lines.txt'.IO.lines[1,7,3].join(qq~\n~); "
> > Line 1
> > Line 7
> > Line 3
> >
> > a
> >
> > Andy Bach, BS, MSCMECFA
> > Systems Mangler
> > Internet: andy_b...@wiwb.uscourts.gov<mailto:andy_b...@wiwb.uscourts.gov
> >
> > Voice: (608) 261-5738, Cell: (608) 658-1890
> >
> > Every man has the right to an opinion but no man
> > has a right to be wrong in his facts. Nor, above all,
> > to persist in errors as to facts. Bernard Baruch
> >
> > ________________________________
> > From: ToddAndMargo via perl6-users <perl6-us...@perl.org>
> > Sent: Monday, August 24, 2020 9:35 PM
> > To: perl6-users <perl6-us...@perl.org>
> > Subject: print particular lines question
> >
> > Hi All,
> >
> > I seems I should know how to do this, but
> > I am drawing a blank.
> >
> > $ cat Lines.txt | raku -ne 'say $_;'
> > Line 1
> > Line 2
> > Line 3
> > Line 4
> > Line 5
> > Line 6
> > Line 7
> > Line 8
> > Line 9
> > Line 10
> > Line 11
> >
> >
> > I want to print liens 1, 3, and 7.
> >
> > Assigning `my @x=$_.lines` puts everything into $x[0]
> >
> >
> > Many thanks,
> > -T
> >
>
