Beefy Boxes and Bandwidth Generously Provided by pair Networks
go ahead... be a heretic
 
PerlMonks  

Re^3: Difference between for and foreach

by runrig (Abbot)
on Jun 13, 2013 at 19:47 UTC ( #1038832=note: print w/replies, xml ) Need Help??


in reply to Re^2: Difference between for and foreach
in thread Difference between for and foreach

That comment is about the C-style for loops ( e.g. for ( $i = 0; $i < $j; $i++) versus iterating directly over a list ( e.g. for my $item (@array) ).

Replies are listed 'Best First'.
Re^4: Difference between for and foreach
by skaurus (Novice) on Nov 11, 2013 at 14:07 UTC
    Thanks! I expected a notification email, didn't received one and because of this I saw your answer just now.

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://1038832]
help
Chatterbox?
[Corion]: You'll have to look somewhere esoteric for that. Maybe some tied variable or special dualvar can also trigger that. But it's certainly not a common occurrence
[Corion]: And on 5.20, the following also outputs no find:perl -wle 'for my $x ("\x{2000}".."\ x{1fffff}") { if( $x && ! length $x ) { warn qq(<$x>); warn length $x; die } }'
[Corion]: (this time on Unix)
[hippo]: Understood. I'll have to go through the code and see if it's doing anything fancy with ties, dual-vars or non-scalars. In the end, it's probably a bug though.
[Corion]: Aaah - you should be able to do this with overload, but I would hit somebody really hard if they constructed objects that are true but the empty string, and you not knowing about the domain knowledge where this makes sense
[Eily]: you could tie a variable into not having the same value each time, if you like to make people who try to debug your code facepalm
[Corion]: perl -wle 'package o; use overload q("") => sub {warn "str"; ""}, bool => sub{warn "bool"; 1}; package main; my $o={}; bless $o => o; print "Yay" if ($o && !length($o))'
[Corion]: But people writing such code should document the objects they construct and why it makes sense for an object to be invisible as string while being true in a boolean context

How do I use this? | Other CB clients
Other Users?
Others contemplating the Monastery: (14)
As of 2017-07-27 13:34 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    I came, I saw, I ...
























    Results (413 votes). Check out past polls.