Interesting. Let me know if I've got this strait: 
#!/usr/bin/perl -w

use strict;

sub i_am_a_number {
    shift;
    no warnings; # += 0 on a string sets off a warning

    # make sure that zero is counted as a number
    # ($_ += 0) alone fails on zero.
    if (/^\d+$/ || ($_ += 0)) {
        return 1;
    }
    return 0;
}

#############################################################
# take the sub on a test spin
my @list = (035, 35, +19, 12, "045", -2, 5.5, 0, -34.530, "hi!");

for (@list) {
    if (i_am_a_number($_)) {
        print "$_ is a number!\n";
    } 
}

[download]
Does this pass muster for zero, signed, and float type numbers? 
()-()
 \"/
  `

In reply to Re: Re: How to determine a variable value is a number by ignatz
in thread How to determine a variable value is a number by ciamack

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