大约有 30,000 项符合查询结果（耗时：0.0318秒） [XML]
How to use R's ellipsis feature when writing your own function?
... for defining functions that can take a variable number of arguments. For em>x m>ample, the function data.frame takes any number of arguments, and each argument becomes the data for a column in the resulting data table. Em>x m>ample usage:
...
Convert nested Python dict to object?
...a dict with some nested dicts and lists (i.e. javascript-style object syntam>x m>).
39 Answers
...
What does |= (ior) do in Python?
...R, binary operation
In most cases, it is related to the | operator. See em>x m>amples below.
Sets
For em>x m>ample, the union of two assigned sets s1 and s2 share the following equivalent em>x m>pressions:
>>> s1 = s1 | s12 # 1
>>> s1 |= s2 ...
How do I call one constructor from another in Java?
...
Yes, it is possible:
public class Foo {
private int m>x m>;
public Foo() {
this(1);
}
public Foo(int m>x m>) {
this.m>x m> = m>x m>;
}
}
To chain to a particular superclass constructor instead of one in the same class, use super instead of this. Note that you c...
Nested defaultdict of defaultdict
...ber of levels:
def rec_dd():
return defaultdict(rec_dd)
>>> m>x m> = rec_dd()
>>> m>x m>['a']['b']['c']['d']
defaultdict(<function rec_dd at 0m>x m>7f0dcef81500>, {})
>>> print json.dumps(m>x m>)
{"a": {"b": {"c": {"d": {}}}}}
Of course you could also do this with a lambda, but ...
Where and why do I have to put the “template” and “typename” keywords?
...why do I have to put typename and template on dependent names?
What em>x m>actly are dependent names anyway?
6 Answers
...
What are good uses for Python3's “Function Annotations”
...no constructs that made this straightforward and part of the official syntam>x m>.
There are other uses for annotations beyond assurance. I can see how I could apply my Java-based tools to Python. For instance, I have a tool that lets you assign special warnings to methods, and gives you indications wh...
C# 4.0 optional out/ref arguments
...ication, section 21.1:
Formal parameters of constructors, methods, indem>x m>ers and delegate types can be declared optional:
fim>x m>ed-parameter:
attributesopt parameter-modifieropt type identifier default-argumentopt
default-argument:
= em>x m>pression
A fim>x m>ed-parameter ...
iPhone UIButton - image position
I have a UIButton with tem>x m>t "Em>x m>plore the app" and UIImage (>)
In Interface Builder it looks like:
15 Answers
...
How do I em>x m>tract a sub-hash from a hash?
...
If you specifically want the method to return the em>x m>tracted 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...