7.11. "fpformat" — Floating point conversions
*********************************************

2.6 版后已移除: The "fpformat" module has been removed in Python 3.

The "fpformat" module defines functions for dealing with floating
point numbers representations in 100% pure Python.

注解: This module is unnecessary: everything here can be done using
  the "%" string interpolation operator described in the String
  Formatting Operations section.

The "fpformat" module defines the following functions and an
exception:

fpformat.fix(x, digs)

   Format *x* as "[-]ddd.ddd" with *digs* digits after the point and
   at least one digit before. If "digs <= 0", the decimal point is
   suppressed.

   *x* can be either a number or a string that looks like one. *digs*
   is an integer.

   Return value is a string.

fpformat.sci(x, digs)

   Format *x* as "[-]d.dddE[+-]ddd" with *digs* digits after the
   point and exactly one digit before. If "digs <= 0", one digit is
   kept and the point is suppressed.

   *x* can be either a real number, or a string that looks like one.
   *digs* is an integer.

   Return value is a string.

exception fpformat.NotANumber

   Exception raised when a string passed to "fix()" or "sci()" as the
   *x* parameter does not look like a number. This is a subclass of
   "ValueError" when the standard exceptions are strings.  The
   exception value is the improperly formatted string that caused the
   exception to be raised.

Example:

   >>> import fpformat
   >>> fpformat.fix(1.23, 1)
   '1.2'
