Perl 5 version documentation

log

Perl functions A-Z | Perl functions by category | The 'perlfunc' manpage
  • log EXPR

  • log

    Returns the natural logarithm (base e) of EXPR. If EXPR is omitted, returns the log of $_ . 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:

    1.     sub log10 {
    2.         my $n = shift;
    3.         return log($n)/log(10);
    4.     }

    See also exp for the inverse operation.