Get logarithm of base 10

[tamaguchi]

Hello all As I know it natural logarithm of a number "$number" is written in perl as: log($numer) but how is it possible to get the logarithm with base 10 or other logartms such as with base 2 etc. Thank you for any help.

2006-02-28 Retitled by jdporter, as per Monastery guidelines
Original title: 'Logarithms'

[dempa]

From "perldoc -f log":

To get the log of another base, use basic algebra: The base-N log of a number is equal to the natural log of that number divided by the natural log of N. For example:

  sub log10 {
    my $n = shift;
    return log($n)/log(10);
  }

[northwind]

Or if you wanted base N (where N could be 2, π, 10, 16, etc.)...

sub log_N
{
  my $num = shift;
  my $base = shift;
  return log($num)/log($base);
}

[ChemBoy]

As an alternative to the techniques already mentioned, you could always use POSIX 'log10'; (assuming that's not too easy ;-).