Re^4: Binary to decimal conversion

[andreas1234567]

in reply to Re^3: Binary to decimal conversion
in thread Binary to decimal conversion

In list context:

my @array = reverse( LIST );

In scalar context:

my $value = reverse( LIST );

Fine. But it does not say how it's supposed to behave when fed a SCALAR instead of a LIST, does it?

I'm still confused.

[Fletch]

Erm . . . a LIST may consist of a single scalar value. That single scalar value is concatenated with all the other elements in the LIST (very quickly, obviously, since they're non-existent) and the bytes in that concatenated string (i.e. the single scalar argument) are returned in reverse order, just like the docs say.

[andreas1234567]

Then tell me why this prints hello and not olleh?

$ perl -wle 'print reverse(q{hello})'
hello

[Fletch]

Because print takes a LIST and hence provides a list context to reverse which triggers the list context behavior from the latter (and a 1 element list reversed is indistinguishable from the original 1 element list for obvious reasons). Stick a scalar in there after the print, and/or store the reverse into a scalar temporary variable, and you'll see the behavior you're expecting.

[Anonymous Monk]

Because you did not RTFM :)

reverse LIST
        In list context, returns a list value consisting of the elemen
+ts
        of LIST in the opposite order. In scalar context, concatenates
        the elements of LIST and returns a string value with all
        characters in the opposite order.

            print reverse <>;           # line tac, last line first

            undef $/;                   # for efficiency of <>
            print scalar reverse <>;    # character tac, last line tsr
+if

        Used without arguments in scalar context, reverse() reverses $
+_.

        This operator is also handy for inverting a hash, although the
+re
        are some caveats. If a value is duplicated in the original has
+h,
        only one of those can be represented as a key in the inverted
        hash. Also, this has to unwind one hash and build a whole new
        one, which may take some time on a large hash, such as from a
        DBM file.

            %by_name = reverse %by_address;     # Invert the hash