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Re^3: Array got modified!

by Jenda (Abbot)
on Oct 10, 2011 at 10:25 UTC ( #930575=note: print w/replies, xml ) Need Help??


in reply to Re^2: Array got modified!
in thread Array got modified!

Could you explain, in your own words, what does the while ( my $ele = <@arr> ) { do?

Once you do, go check the docs!

It may seem to do what you seem to want if you are unlucky enough and the @arr doesn't contain anything interesting to the diamond operator, but even then it's horribly inefficient.

Jenda
Enoch was right!
Enjoy the last years of Rome.

Replies are listed 'Best First'.
Re^4: Array got modified!
by exilepanda (Pilgrim) on Oct 10, 2011 at 12:51 UTC
    Hmm... my try is to take that array as a file handle to read, like @ARGV;

    I add up this code :

    @x = qw/Foo Bar Blaz/; #@x = qw//; print "Before: @x$/"; while ( my $ele = <@x> ) { next unless $ele; print "$ele becomes "; $ele =~ s/^(.)/x$1/; print $ele . $/; } print "$/After: @x"; __END__ Then I have : Before: Foo Bar Blaz Foo becomes xFoo Bar becomes xBar Blaz becomes xBlaz After: Foo Bar Blaz
    Is this work out properly by accident? This is what I want though...
    My observation is:
    if that's a empty array, it skips fine.
    And, without the diamond quote, it loops forever...
      $ perl -MO=Deparse junk print "Before: @x$/"; use File::Glob (); while (defined(my $ele = glob(join $", @x))) { do { next unless $ele; print "$ele becomes "; $ele =~ s/^(.)/x$1/; print $ele . $/ }; } print "$/After: @x"; __DATA__ junk syntax OK

      See glob, readline

        Sorry but I don't get it.

        First, after a perldoc on the glob, I get totally lost, I never touch a Unix shell, so I couldn't imagine or relate to anything.. I am on Win32 all time..

        Second, would you explain more for what is your code try to demonstrate? Is this a safe/suggested way to do what I want? or it's proving my way is danger? or anything else ?

      Yes, it's working by accident (no spaces nor * in @x). For example:
      perl -E '@arr=("a b", "c d", qw/e f g h a*/); while (my $e = <@arr>) { say $e }'
      gives this output for me:
      a b c d e f g h address.txt address.txt~ analytic ascii.htm aux-no-lex.lst
        Got it! Didn't aware of it at all....
        Lesson learned!! Thanks a lot!!! =)

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