I had to confirm what $x=!!$y meant in perl. Remarkably, typing !! or "!!" or !! into google gives you nothing. Had to use English.
Got this:
http://stackoverflow.com/questions/2168406/what-does-double-exclamation-poin...
The +42 answer is quite good. Exec summary: !! is good for cleaning vars into 1 (true) or '' (false), which is important to keep warnings from complaining about undef vars.
Anyhow, read the comments in the +42 answer. Hehehe.
Let the flamewars begin!
Thanks for pointing that out. TIL --> which is another example of "two operators smashed together does something cool". Too bad it doesn't work in Ruby, but it does in Perl:
$ perl -e '$x=3; print "hi\n" while ($x --> 0)' hi hi hi
Sean
On Sat, Feb 28, 2015 at 1:38 AM, Trevor Cordes trevor@tecnopolis.ca wrote:
I had to confirm what $x=!!$y meant in perl. Remarkably, typing !! or "!!" or !! into google gives you nothing. Had to use English.
Got this:
http://stackoverflow.com/questions/2168406/what-does-double-exclamation-poin...
The +42 answer is quite good. Exec summary: !! is good for cleaning vars into 1 (true) or '' (false), which is important to keep warnings from complaining about undef vars.
Anyhow, read the comments in the +42 answer. Hehehe.
Let the flamewars begin! _______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
Ruby is less terse (I prefer to say more readable) and many of its idioms involve words. However, a = !!b assigns the boolean value of b, and a ||= b assigns b to a only if a is nil or false (at the risk of being less readable)
-Dan
On Sat, Feb 28, 2015 at 8:53 AM, Sean Walberg sean@ertw.com wrote:
Thanks for pointing that out. TIL --> which is another example of "two operators smashed together does something cool". Too bad it doesn't work in Ruby, but it does in Perl:
$ perl -e '$x=3; print "hi\n" while ($x --> 0)' hi hi hi
Sean
On Sat, Feb 28, 2015 at 1:38 AM, Trevor Cordes trevor@tecnopolis.ca wrote:
I had to confirm what $x=!!$y meant in perl. Remarkably, typing !! or "!!" or !! into google gives you nothing. Had to use English.
Got this:
http://stackoverflow.com/questions/2168406/what-does-double-exclamation-poin...
The +42 answer is quite good. Exec summary: !! is good for cleaning vars into 1 (true) or '' (false), which is important to keep warnings from complaining about undef vars.
Anyhow, read the comments in the +42 answer. Hehehe.
Let the flamewars begin! _______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
-- Sean Walberg sean@ertw.com http://ertw.com/
Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
More on secret perl operators: http://search.cpan.org/~book/perlsecret-1.012/lib/perlsecret.pod
Heed the word of warning!
Chris
On Sat, 28 Feb 2015, Trevor Cordes wrote:
I had to confirm what $x=!!$y meant in perl. Remarkably, typing !! or "!!" or !! into google gives you nothing. Had to use English.
Got this:
http://stackoverflow.com/questions/2168406/what-does-double-exclamation-poin...
The +42 answer is quite good. Exec summary: !! is good for cleaning vars into 1 (true) or '' (false), which is important to keep warnings from complaining about undef vars.
Anyhow, read the comments in the +42 answer. Hehehe.
Let the flamewars begin! _______________________________________________ Roundtable mailing list Roundtable@muug.mb.ca http://www.muug.mb.ca/mailman/listinfo/roundtable
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Chris Lawson -
Dan Martin -
Sean Walberg -
Trevor Cordes