Re^3: Braino - why is this not working?

It's the $_ from the 'foreach' from the array that is passed.

The closes such construct is the map, not the foreach

my @a = 1 .. 3;
my @res = 0;
for(@a){
   my $ans = grep {
    warn ">>$_<< ";
    /^$_$/
   } @res;
   warn "ans >>>$ans<<< "
}
__END__
>>0<<  at - line 4.
ans >>>1<<<  at - line 8.
>>0<<  at - line 4.
ans >>>1<<<  at - line 8.
>>0<<  at - line 4.
ans >>>1<<<  at - line 8.
[download]

Comment on Re^3: Braino - why is this not working? Download Code

Replies are listed 'Best First'.
not exactly, but yeah, anyway... ;-) by perl-diddler (Chaplain) on Oct 19, 2010 at 03:35 UTC
Details slightly off, but the essence was it. Detail: the foreach works sets "$_" to each value in the list, in turn `print "_=$_\n" for (1..3);` [download] but ... Your post hit the reason for the problem. "Grep" sets $_ to each member in turn, so searching for '$_' will always return 'true' if you search on /$_/; Absolutely simple, got caught with my 1 'register' var being double used. Sigh. Thinking about the simplicity of using $_ in 'foreach', I forgot about grep...sigh. MUCH thanks -- very it was driving me crazy!	[reply] [d/l]

Replies are listed 'Best First'.

not exactly, but yeah, anyway... ;-)
by perl-diddler (Chaplain) on Oct 19, 2010 at 03:35 UTC

Detail: the foreach works sets "$_" to each value in the list, in turn

print "_=$_\n" for (1..3);
[download]

Your post hit the reason for the problem. "Grep" sets $_ to each member in turn, so searching for '$_' will always return 'true' if you search on /$_/;

Absolutely simple, got caught with my 1 'register' var being double used. Sigh. Thinking about the simplicity of using $_ in 'foreach', I forgot about grep...sigh.

MUCH thanks -- very it was driving me crazy!

[reply]
[d/l]