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'