大约有 15,000 项符合查询结果（耗时：0.0460秒） [XML]
Nested defaultdict of defaultdict
...ber of levels:
def rec_dd():
return defaultdict(rec_dd)
>>> x = rec_dd()
>>> x['a']['b']['c']['d']
defaultdict(<function rec_dd at 0x7f0dcef81500>, {})
>>> print json.dumps(x)
{"a": {"b": {"c": {"d": {}}}}}
Of course you could also do this with a lambda, but ...
C# 4.0 optional out/ref arguments
...ication, section 21.1:
Formal parameters of constructors, methods, indexers and delegate types can be declared optional:
fixed-parameter:
attributesopt parameter-modifieropt type identifier default-argumentopt
default-argument:
= expression
A fixed-parameter ...
How do I extract a sub-hash from a hash?
...
If you specifically want the method to return the extracted elements but h1 to remain the same:
h1 = {:a => :A, :b => :B, :c => :C, :d => :D}
h2 = h1.select {|key, value| [:b, :d, :e, :f].include?(key) } # => {:b=>:B, :d=>:D}
h1 = Hash[h1.to_a - h2.to_a...
iPhone UIButton - image position
I have a UIButton with text "Explore the app" and UIImage (>)
In Interface Builder it looks like:
15 Answers
...
How to get first element in a list of tuples?
...st(unzipped[0])
[1, 2]
Edit (@BradSolomon):
The above works for Python 2.x, where zip returns a list.
In Python 3.x, zip returns an iterator and the following is equivalent to the above:
>>> print(list(list(zip(*inpt))[0]))
[1, 2]
...
Using do block vs braces {}
...
Ruby cookbook says bracket syntax has higher precedence order than do..end
Keep in mind that the bracket syntax
has a higher precedence than the
do..end syntax. Consider the following
two snippets of code:
1.upto 3 do |x|
puts x
end
1.upto 3 ...
what is Promotional and Feature graphic in Android Market/Play Store?
...it mean and need whether we are uploading our app into the market? Please Explain or give me a related links.
7 Answers
...
Determining memory usage of objects? [duplicate]
...time ago I stole this little nugget from here:
sort( sapply(ls(),function(x){object.size(get(x))}))
it has served me well
share
|
improve this answer
|
follow
...
Compiling simple Hello World program on OS X via command line
I've got a simple hello world example that I'm trying to compile on OS X, named hw.cpp :
8 Answers
...