Python 3000 deat！？是真正的分裂吗？ [英] Python 3000 deat !? Is true division ever coming ?
问题描述
Python 3000是真的吗？已经死了？
老实说，我认为，例如将5/2改为2.5（而不是2）将会打破很多代码:-(
另一方面我用Python作为Matlab替换并且将
一般像5/2 == 2.5
因此，我正在考虑默认我的所有模块/脚本以
"来自__future__进口部门
但是如果它永远不会到来（在这十年中，那就是）那么这将是一个浪费时间的b / b
只是让每个人感到困惑!!
谢谢，
Sebastian Haase
Hi,
Is it true that that "Python 3000" is dead ?
Honestly I think that e.g. changing 5/2 to be 2.5 (instead of 2) would
just break to much code :-(
On the otherhand I''m using Python as "Matlab replacement" and would
generally like 5/2 ==2.5
So, I was contemplating to default all my modules/scripts to start with
"from __future__ import division"
but if it is never coming (in this decade, that is) then it would be a
waste of time just confuse everybody !!
Thanks,
Sebastian Haase
推荐答案
se*******@gmail.com 写道：
是不是Python 3000已经死了？
老实说，我认为例如将5/2改为2.5（而不是2）将会打破很多代码:-(
另一方面，我使用Python作为Matlab替换，并且
通常喜欢5/2 == 2.5
...
Hi,
Is it true that that "Python 3000" is dead ?
Honestly I think that e.g. changing 5/2 to be 2.5 (instead of 2) would
just break to much code :-(
On the otherhand I''m using Python as "Matlab replacement" and would
generally like 5/2 ==2.5
...
这是比较。科学。 101，基于三年级算术，而不是Python。
5/2 = 2是整数除法，这是整数运算的工作方式。
5./2 。= 2.5是浮点数学，具有
合并的所有舍入误差。
如果Matlab假设浮点数，则那就是你的意思'支付
大笔钱。
柯蒂斯
It''s Comp. Sci. 101, based on third grade artithmetic, not Python.
5/2=2 is integer division, that''s the way integer arithmetic works.
5./2.=2.5 is floating point math, with all the round off errors that
incorporates.
If Matlab assumes floating point, then that''s what you''re paying the
big bucks for.
Curtis
开2006年2月14日06:44:02 -0800， ra ************ @ gmail.com
On 14 Feb 2006 06:44:02 -0800, ra************@gmail.com
5./2.=2.5是浮点数学，包含
包含的所有舍入错误。
5./2.=2.5 is floating point math, with all the round off errors that
incorporates.
谢谢Curtis，我从来不知道这个伎俩。我想变量确实有
真正的除法你必须让它们漂浮？例如
float（var1）/ float（var2）？或者你知道一个不那么打字的方法吗？
那个？
-
Gregory Pi？ero
首席创新官
混合技术
（ www.blendedtechnologies.com ）
Gregory Pi？ero写道：
Gregory Pi?ero wrote:
2006年2月14日06:44:02 - 0800， ra************@gmail.com
On 14 Feb 2006 06:44:02 -0800, ra************@gmail.com
5./2.=2.5是浮点数学，包含
包含的所有舍入错误。
5./2.=2.5 is floating point math, with all the round off errors that
incorporates.
Thanks Curtis, I never knew that trick. I guess for variables do have
true division you have to make them floats? e.g.
float(var1)/float(var2)? Or do you know a less typing approach for
that?
Googlepython true division - >我很幸运：
http://www.python.org/doc/2.2.3/whatsnew/node7.html
来自网页：
"""
*通过在模块（*）中包含__future__导入部门，/
运算符将被更改返回真正除法的结果，所以1/2
是0.5。没有__future__声明，/仍然意味着经典的
除法。在Python 3.0之前，/的默认含义不会改变。
"""
*作为第一个非文档字符串/非注释行。
请注意，那是'模块 - 交互式解释器不会
以相同的方式响应来自__future__ import ;声明。
Google "python true division" -> I''m feeling lucky:
http://www.python.org/doc/2.2.3/whatsnew/node7.html
From the web page:
"""
* By including a from __future__ import division in a module(*), the /
operator will be changed to return the result of true division, so 1/2
is 0.5. Without the __future__ statement, / still means classic
division. The default meaning of / will not change until Python 3.0.
"""
*As the first non-docstring/non-comment line.
Note that that''s for a module -- the interactive interpreter won''t
respond the same way to the "from __future__ import" statement.
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