On 2020-08-31 16:57, ToddAndMargo via perl6-users wrote:
On 2020-08-31 16:53, ToddAndMargo via perl6-users wrote:
On Mon, Aug 31, 2020, 4:20 PM ToddAndMargo via perl6-users
<perl6-users@perl.org <mailto:perl6-users@perl.org>> wrote:
On 2020-08-31 05:53, Brian Duggan wrote:
> On Monday, August 24, Curt Tilmes wrote:
>> $ cat Lines.txt | raku -e '.say for lines()[3,2,5]'
>
> The -n flag is an option here too:
>
> raku -ne '.say if $++ == 3|2|5' Lines.txt
>
> Brian
>
Hi Bill,
Works beatifically! And no bash pipe!
$ raku -ne '.say if $++ == 3|2|5' Lines.txt
Line 2
Line 3
Line 5
What is `$++`?
-T
On 2020-08-31 16:36, yary wrote:
$ by itself is an anonymous variable, putting ++ after starts it at 0
(hmm or nil?) and increments up.
By putting the plus plus first, ++$, it will start at 1, thanks to
pre-increment versus post increment
Hi Yary,
Excellent instructions! It is a counter. I found
it over on
https://docs.raku.org/perl6.html
with a search on `$++`. But I had to pick it up
from "context"
$ p6 'my @x=<"a" "b" "c">; for @x -> $i { print $++," ", ++$, " ", $i,
"\n";}'
0 1 "a"
1 2 "b"
2 3 "c"
Question: does the counter restart after its use, or do
I need to do it myself?
-T
To answer my own question. It resets itself:
$ p6 'my @x=<"a" "b" "c">; for @x -> $i { print $++, " ", ++$, " ", $i,
"\n" }; print "\n", $++, "\n";'
0 1 "a"
1 2 "b"
2 3 "c"
0
perl6.++.counters.txt
++ counters:
$++ adn ++$ are both anonymous variables
`$++` is a counter that start at zero and increments by 1
`++$` is a counter that start at one and increments by 1
and the reset themselves.
For example:
$ p6 'my @x=<"a" "b" "c">;
for @x -> $i { print $++, " ", ++$, " ", $i, "\n" };
print "\n", $++, "\n";'
0 1 "a"
1 2 "b"
2 3 "c"
0
