大约有 13,906 项符合查询结果（耗时：0.0333秒） [XML]
Why aren't python nested functions called closures?
... access to a local variable from an enclosing scope that has finished its execution.
def make_printer(msg):
def printer():
print msg
return printer
printer = make_printer('Foo!')
printer()
When make_printer is called, a new frame is put on the stack with the compiled code for the...
jQuery deferreds and promises - .then() vs .done()
... information on pipe().
success() and error() are only available on the jqXHR object returned by a call to ajax(). They are simple aliases for done() and fail() respectively:
jqXHR.done === jqXHR.success
jqXHR.fail === jqXHR.error
Also, done() is not limited to a single callback and will filter ...
Remove empty strings from a list of strings
...ythonic way:
>>> strings = ["first", "", "second"]
>>> [x for x in strings if x]
['first', 'second']
If the list must be modified in-place, because there are other references which must see the updated data, then use a slice assignment:
strings[:] = [x for x in strings if x]
...
What is 'Currying'?
...o curried functions in several articles and blogs but I can't find a good explanation (or at least one that makes sense!)
1...
In R, how to get an object's name after it is sent to a function?
...
The old deparse-substitute trick:
a<-data.frame(x=1:10,y=1:10)
test<-function(z){
mean.x<-mean(z$x)
nm <-deparse(substitute(z))
print(nm)
return(mean.x)}
test(a)
#[1] "a" ... this is the side-effect of the print() call
# ... you could have...
How do I put two increment statements in a C++ 'for' loop?
... operator at all. I checked that in GCC as follows:
int i=0;
int a=5;
int x=0;
for(i; i<5; x=i++,a++){
printf("i=%d a=%d x=%d\n",i,a,x);
}
I was expecting x to pick up the original value of a, so it should have displayed 5,6,7.. for x. What I got was this
i=0 a=5 x=0
i=1 a=6 x=0
i=2 a=7 ...
Elegant way to combine multiple collections of elements?
...rary number of collections, each containing objects of the same type (for example, List<int> foo and List<int> bar ). If these collections were themselves in a collection (e.g., of type List<List<int>> , I could use SelectMany to combine them all into one collection.
...
How to determine if a point is in a 2D triangle? [closed]
...ou started:
float sign (fPoint p1, fPoint p2, fPoint p3)
{
return (p1.x - p3.x) * (p2.y - p3.y) - (p2.x - p3.x) * (p1.y - p3.y);
}
bool PointInTriangle (fPoint pt, fPoint v1, fPoint v2, fPoint v3)
{
float d1, d2, d3;
bool has_neg, has_pos;
d1 = sign(pt, v1, v2);
d2 = sign(pt, ...
How to count certain elements in array?
... just to compare it to a value is not elegant.
– Felix Kling
May 25 '11 at 8:33
2
...
Combine two columns of text in pandas dataframe
I have a 20 x 4000 dataframe in Python using pandas. Two of these columns are named Year and quarter . I'd like to create a variable called period that makes Year = 2000 and quarter= q2 into 2000q2 .
...