大约有 14,100 项符合查询结果（耗时：0.0273秒） [XML]
What is the best (idiomatic) way to check the type of a Python variable? [duplicate]
...se collections.Mapping instead of dict as per the ABC PEP.
def value_list(x):
if isinstance(x, dict):
return list(set(x.values()))
elif isinstance(x, basestring):
return [x]
else:
return None
...
YAML mime type?
...
Ruby on Rails uses application/x-yaml with an alternative of text/yaml (source).
I think it's just a matter of convention, there is no technical why, as far as I can tell.
share
...
How to fix the aspect ratio in ggplot?
...he mechanism to preserve the aspect ratio of your plot is to add a coord_fixed() layer to the plot. This will preserve the aspect ratio of the plot itself, regardless of the shape of the actual bounding box.
(I also suggest you use ggsave to save your resulting plot to pdf/png/etc, rather than the...
How to add an object to an array
How can I add an object to an array (in javascript or jquery)?
For example, what is the problem with this code?
13 Answ...
Can I call a constructor from another constructor (do constructor chaining) in C++?
...onwards has this same feature (called delegating constructors).
The syntax is slightly different from C#:
class Foo {
public:
Foo(char x, int y) {}
Foo(int y) : Foo('a', y) {}
};
C++03: No
Unfortunately, there's no way to do this in C++03, but there are two ways of simulating this:
You ...
str performance in python
... 3 ('100000')
3 RETURN_VALUE
% with a run-time expression is not (significantly) faster than str:
>>> Timer('str(x)', 'x=100').timeit()
0.25641703605651855
>>> Timer('"%s" % x', 'x=100').timeit()
0.2169809341430664
Do note that str is still slightly sl...
How to use the IEqualityComparer
...m without duplication. I created a compare class to do this work, but the execution of the function causes a big delay from the function without distinct, from 0.6 sec to 3.2 sec!
...
How do you perform a left outer join using linq extension methods
... foo => foo.Foo_Id,
bar => bar.Foo_Id,
(x,y) => new { Foo = x, Bars = y })
.SelectMany(
x => x.Bars.DefaultIfEmpty(),
(x,y) => new { Foo=x.Foo, Bar=y});
...
Simple explanation of MapReduce?
...ry number, in this case, the function to "double every number" is function x = x * 2. And without mappings, I could write a simple loop, say
A = [1, 2, 3]
foreach (item in A) A[item] = A[item] * 2
and I'd have A = [2, 4, 6] but instead of writing loops, if I have a map function I could write
A =...
Why is lazy evaluation useful?
...g been wondering why lazy evaluation is useful. I have yet to have anyone explain to me in a way that makes sense; mostly it ends up boiling down to "trust me".
...