Re^5: filtering an array

[philiprbrenan]

in reply to Re^4: filtering an array
in thread filtering an array

Likewise, the for is unnecessary in this code too:

for (@positions) {@positions = map $_->[0], @positions;}

It should just be:

@positions = map $_->[0], @positions;

because map iterates over the array you give it. Even better, you could write:

$_ = $_->[0] for @positions;

here we are making the for implicit in map explicit.

[prbndr]

perl still has a problem with this:

@positions = grep $_->[1] =~ /ac/i, @positions;

with the same error Use of uninitialized value in pattern match (m//)

[philiprbrenan]

One or more of the elements of the array @positions is undefined. The easiest way to check this is like this:

use Data::Dump qw(pp);

pp([@positions]);

This will give you a printout of the value of each element in array @positions. I expect we will see that some are "undef" meaning undefined. It will be these elements that are causing the problem.

[prbndr]

i don't see any that are "undef. that's a little strange. the data dumper output prints:

9031,

"A"

etc. etc. this is a little strange...