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发表于： **2016-08-17 0:22**

[Python]从教程复制的代码,我这里显示的结果和教程中不同?
教程地址:
https://docs.python.org/3.4/tutorial/in ... formatting
教程的执行结果:

代码：全选

>>> import math
>>> print('The value of PI is approximately {}.'.format(math.pi))
The value of PI is approximately 3.14159265359.
>>> print('The value of PI is approximately {!r}.'.format(math.pi))
The value of PI is approximately 3.141592653589793.

我的执行结果:

代码：全选

Python 3.4.2 (default, Oct  8 2014, 13:14:40) 
[GCC 4.9.1] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import math
>>> print('The value of PI is approximately {}.'.format(math.pi))
The value of PI is approximately 3.141592653589793.
>>> 
>>> print('The value of PI is approximately {!r}.'.format(math.pi))
The value of PI is approximately 3.141592653589793.
>>>

发表于： **2016-08-17 6:10**

1. 猜測
format(math.pi)
Floating Point Arithmetic
precision
不同

2. 參閱
2-1. https://docs.python.org/3.4/library/math.html
9.2.7. Constants
math.pi
The mathematical constant π = 3.141592..., to available precision.
2-2. https://docs.python.org/3.4/tutorial/fl ... -fp-issues
Floating Point Arithmetic: Issues and Limitations
使用 precision 關鍵字搜尋

发表于： **2016-08-17 9:34**

python 3.2之前，str()转换数值默认的精度是12。教程偷懒没更新，直接拿原来版本的例子来用了。

Ubuntu中文论坛

[Python]从教程复制的代码,我这里显示的结果和教程中不同?

[Python]从教程复制的代码,我这里显示的结果和教程中不同?

Re: [Python]从教程复制的代码,我这里显示的结果和教程中不同?

Re: [Python]从教程复制的代码,我这里显示的结果和教程中不同?