说我有这样的字典:
d = {'a': 8.25, 'c': 2.87, 'b': 1.28, 'e': 12.49}
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我有一个价值
v = 3.19
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我想说的是:
x = "the key with the value CLOSEST to v"
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哪会导致
x = 'c'
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有关如何处理此问题的任何提示?
这是我的HTML:
<div class="large">
<img src="/images/photos/Interior.jpg" alt="The interior" style="[...]" />
<div class="caption">The interior</div>
</div>
<div class="small">
<img src="/images/photos/Bedroom.jpg" alt="Bedroom" style="[A different ...]" />
<div class="caption">A bedroom</div>
</div>
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单击a后div.small,我想要图像和标题来交换容器div.问题是我不能只交换src,因为有一些需要保留的内联样式集.最后,一旦交换了图像,我想将自定义函数.fitToParent()应用于它们.
我该怎么做呢?
在我的主协程中,我根据用户操作从表中删除或添加条目.在后台,我想迭代表中的条目.我不介意特别是如果我错过了一次迭代的插入,只要我能在下一次迭代之前捕获它.
迭代它是否安全pairs?或者我应该使用next?
可以转换的东西
r"a+|(?:ab+c)"
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至
{
(1, 'a') : [2, 3],
(2, 'a') : [2],
(3, 'b') : [4, 3],
(4, 'c') : [5]
}
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或类似的东西
并在2或5中接受
是否可以编写一个类,使其有效:
Foo a;
Foo b = 0;
Foo c = b;
Foo d(0);
Foo e(1);
Foo f = Foo(1);
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但这些不是:
int x;
Foo a = x;
Foo b = 1;
Foo c = 2;
//etc
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从本质上讲,我的规则是"一个常量0可以隐式转换为a Foo,但没有其他值"
以下是使用符合Pythonic/pep8的逻辑表达式吗?
这个:
x = a or b
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代替:
if not a:
x = b
else:
x = a
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x = a and b
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代替:
if not a:
x = a
else:
x = b
Run Code Online (Sandbox Code Playgroud)(曲线球?)这个:
x = x or y
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代替:
if not x:
x = y
Run Code Online (Sandbox Code Playgroud)从这个链接我了解到了
当前实现为-5到256之间的所有整数保留一个整数对象数组,当您在该范围内创建一个int时,实际上只返回对现有对象的引用
但是当我尝试为我的会话提供一些示例时,我发现它在赋值和元组解包时表现不同.
这是片段,
Python 2.7.2 (default, Oct 11 2012, 20:14:37)
[GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> a,b = 300,300
>>> a is b
True
>>> c = 300
>>> d = 300
>>> c is d
False
>>>
Run Code Online (Sandbox Code Playgroud) 当我使用DateInterval类时,它返回一个属性名称"d",然后另一个属性名称"Days"我真的很困惑两者之间的区别.有人可以解释一下.
下面是我的代码中返回的对象的示例.
DateInterval(
y =
0
m =
1
d =
1
h =
3
i =
16
s =
6
weekday =
0
weekday_behavior =
0
first_last_day_of =
0
invert =
1
days =
31
special_type =
0
special_amount =
0
have_weekday_relative =
0
have_special_relative =
0
Run Code Online (Sandbox Code Playgroud) 我试图通过Pip卸载Numpy,但出现此错误:
$ pip uninstall numpy
Uninstalling numpy:
/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/numpy-1.6.2-py2.7.egg-info
Proceed (y/n)? y
Exception:
Traceback (most recent call last):
File "/Library/Python/2.7/site-packages/pip-1.3.1-py2.7.egg/pip/basecommand.py", line 139, in main
status = self.run(options, args)
File "/Library/Python/2.7/site-packages/pip-1.3.1-py2.7.egg/pip/commands/uninstall.py", line 54, in run
requirement_set.uninstall(auto_confirm=options.yes)
File "/Library/Python/2.7/site-packages/pip-1.3.1-py2.7.egg/pip/req.py", line 899, in uninstall
req.uninstall(auto_confirm=auto_confirm)
File "/Library/Python/2.7/site-packages/pip-1.3.1-py2.7.egg/pip/req.py", line 495, in uninstall
paths_to_remove.remove(auto_confirm)
File "/Library/Python/2.7/site-packages/pip-1.3.1-py2.7.egg/pip/req.py", line 1518, in remove
renames(path, new_path)
File "/Library/Python/2.7/site-packages/pip-1.3.1-py2.7.egg/pip/util.py", line 293, in renames
shutil.move(old, new)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 302, in move
os.unlink(src)
OSError: [Errno 13] Permission denied: '/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/numpy-1.6.2-py2.7.egg-info'
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不知道从这里开始的最佳方式是什么.我想完全卸载numpy然后重新安装.
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