大约有 41,300 项符合查询结果（耗时：0.0483秒） [XML]
How to avoid reinstalling packages when building Docker image for Python projects?
...
143
Try to build a Dockerfile which looks something like this:
FROM my/base
WORKDIR /srv
ADD ./requ...
How does PHP 'foreach' actually work?
...ction iterate($arr) {
foreach ($arr as $v) {}
}
$outerArr = [0, 1, 2, 3, 4];
iterate($outerArr);
Here, $arr will be duplicated to prevent IAP changes on $arr from leaking to $outerArr. In terms of the conditions above, the array is not a reference (is_ref=0) and is used in two places (refcoun...
Looping over a list in Python
...with sublists in it. I want to print all the sublists with length equal to 3.
4 Answers
...
Test if lists share any items in python
...
322
Short answer: use not set(a).isdisjoint(b), it's generally the fastest.
There are four common...
What is the equivalent of MATLAB's repmat in NumPy
...h multiple dimensions and gives a similar result to matlab. (Numpy gives a 3d output array as you would expect - matlab for some reason gives 2d output - but the content is the same).
Matlab:
>> repmat([1;1],[1,1,1])
ans =
1
1
Python:
In [46]: a = np.array([[1],[1]])
In [47]: n...
How to swap keys and values in a hash
... (in essence, by letting you access keys through values):
{a: 1, b: 2, c: 3}.key(1)
=> :a
If you want to keep the inverted hash, then Hash#invert should work for most situations:
{a: 1, b: 2, c: 3}.invert
=> {1=>:a, 2=>:b, 3=>:c}
BUT...
If you have duplicate values, invert will...
Javascript - remove an array item by value [duplicate]
...
223
You'll want to use JavaScript's Array splice method:
var tag_story = [1,3,56,6,8,90],
id_ta...
Bootstrap 3 breakpoints and media queries
On the Bootstrap 3 media queries documentation it says:
10 Answers
10
...
How to Correctly Use Lists in R?
...:
Why do these two expressions not return the same result?
x = list(1, 2, 3, 4); x2 = list(1:4)
A list can contain any other class as each element. So you can have a list where the first element is a character vector, the second is a data frame, etc. In this case, you have created two different ...