蟒蛇2.5：如何将浮点数转换为十六进制？ [英] python 2.5: how to convert float to hex?

问题描述

我想用python 2.4 / 2.5转换一个float（ time.time（））输出。

我发现了很多将hex转换为float的例子，但是我找不到任何可以执行python> =>的 float.hex（） 2.6是不可以的。

解决方案

它需要Python 2.6中新增的sys.float_info中的信息。

如果你想做非易携的，也就是说为你的特定平台，你需要查看用于生成2.4 / 5 Python的C编译器的 float.h 文件，或者查看2.6或2.7实现返回的sys.float_info你的平台（并相信它适用于你的2.4 / 5 Python）。然后你需要查看Python源文件（Objects / floatobject.c）中的 float_hex 函数，并将其转换为Python并对其进行测试（针对2.6 / 7的Python，也许）。

这似乎很多工作，为什么？你的目标是什么？你想做什么不能用 repr（your_float）？

编辑：需要一个唯一的标识符

注意time.time（）不是很精确：

< （）
time.time（）
返回时间，以时间为单位，以UTC表示的浮点数以秒为单位。请注意，即使时间总是作为浮点数返回，并不是所有的系统都能提供比1秒更好的精确时间，而这个函数通常返回非递减的值，如果系统时钟已经在两次调用之间设置了，那么它可以返回比先前调用更低的值$ b $
$ b $ p $允许高达十亿分之一秒的分辨率：

 >>> （int（time.time（）* 1000000000））
'0x11ef11c41cf98b00L'
>>> 
  

是否足够好？

I want to convert a float (the output of time.time()) in hex using python 2.4/2.5.

I found tons of examples that convert hex to float, but I cannot find anything that allows me to do what the float.hex() of python >= 2.6 does.

解决方案

It can't be done portably in Python before version 2.6; it needs the information in sys.float_info, which is new in Python 2.6.

If you want to do it non-portably, i.e. for your particular platform, you would need to look at the float.h file for the C compiler that was used to produce your 2.4/5 Python, or at the sys.float_info returned by a 2.6 or 2.7 implementation on your platform (and trust that it applies to your 2.4/5 Python). Then you would need to look at the float_hex function in the Python source (Objects/floatobject.c) and translate that to Python and test it (against a 2.6/7 Python, perhaps).

This seems like a lot of work, for what? What is your goal? What do you want to do that can't be achieved with repr(your_float)?

Edit: need for a unique identifier

Note that time.time() is not very precise:

""" time.time() Return the time as a floating point number expressed in seconds since the epoch, in UTC. Note that even though the time is always returned as a floating point number, not all systems provide time with a better precision than 1 second. While this function normally returns non-decreasing values, it can return a lower value than a previous call if the system clock has been set back between the two calls. """

Allowing for up to a billionth of a second resolution:

>>> hex(int(time.time() * 1000000000))
'0x11ef11c41cf98b00L'
>>>

Is that good enough?

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