From the perl cookbook section 2.1, with my own reformatting and comments: 
sub isThisADecimalNumber {
    my ($string) = @_;

    return $string =~ /^\s*
                        -?              # negative sign - optional
                        (?:
                            \d+         # digits
                            (?:\.\d*)?  # and an optional decimal and 
+maybe more digits
                        |               # OR
                            \.\d+       # a decimal and some digits
                        )
                        \s*$/x;
}

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In reply to Re: dependable way to test for a float by shemp
in thread dependable way to test for a float by vindaloo

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