If I want to read array elements from lines of input, and I intend to treat each element as a numeric value, I'd load the array from the file like this (assuming that the input is coming from STDIN or from any file(s) named on the command line when I run the script):

use Scalar::Util 'looks_like_number';

my @array;
while (<>) {
    chomp;
    if ( looks_like_number( $_ )) {
        push @array, $_;
    }
    else {  # skip this part if you don't care to know about bad input
+...
        warn "Unusable input line skipped: $_\n";
    }
}
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It doesn't matter to me what the input looks like or where it comes from. When I expect it to be of a certain type, I test to see that it really is that type before I actually use it (i.e. I seldom treat data files or STDIN as "trusted" sources).

UPDATE: Having played with that snippet a bit, I'm happy to notice that leading and trailing whitespace characters do not affect the results of "looks_like_number()" (i.e. it returns true for " 123 ", "\t-456\n", and so on). The same is true for arithmetic operators: you can add, subtract, multiply and divide numeric strings that have leading and trailing whitespace.