比较字符串在Python中浮动 [英] Compare string to float in Python

问题描述

我在python shell中试过这个功能。

 >>> a ='apple'
>>> b = 11.1 
>>> a> b 
 True 
>>> a 
'apple'
>>> b> a 
 False 
  

有人可以向我解释 a> ; b 是真的？当 a 是一个字符串，而 b 是float。

解决方案

不同类型的元素之间的顺序比较是Python 2.x中的一个设计错误，在Python 3中已经被移除（在运行时出现错误）。 b
$ b

在3.x之前修正它并不是一个选项，因为有很多现有的软件在异构容器上进行排序（版本3是第一个故意向后兼容的文件）。

在Python 2.x中，您可以比较< / > ，唯一例外的情况是明确禁止的复数。

不同类型比较的排序结果是任意的，但至少为Python解释器的一个给定的运行，参见 http：//docs.python。 org / 2 / reference / expressions.html＃not-in 。不同的非数字类型的值总是被认为是不同的。

I tried this in python shell

>>> a='apple'
>>> b=11.1
>>> a>b
True
>>> a
'apple'
>>> b>a
False

Can someone explain to me how a>b is True? When a is an string and b is float.

解决方案

Order comparison between elements of different types was a "design bug" in Python 2.x that has been removed in Python 3 (where you get a runtime error).

Correcting it wasn't an option before 3.x because of a lot of existing software that does sorting on heterogeneous containers (and version 3 is the first in which backward compatibility is intentionally broken).

In Python 2.x you can compare anything for </>, with the only exception of complex numbers where this is explicitly forbidden.

The ordering result of comparison of different types is arbitrary but fixed at least for a given run of the Python interpreter, see http://docs.python.org/2/reference/expressions.html#not-in . Values of different non-numeric types are always considered different.

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