大约有 45,000 项符合查询结果（耗时：0.0503秒） [XML]
A clean, lightweight alternative to Python's twisted? [closed]
A (long) while ago I wrote a web-spider that I multithreaded to enable concurrent requests to occur at the same time. That was in my Python youth, in the days before I knew about the GIL and the associated woes it creates for multithreaded code (IE, most of the time stuff just ends up serialized!...
JavaScript checking for null vs. undefined and difference between == and ===
...
How do I check a variable if it's null or undefined...
Is the variable null:
if (a === null)
// or
if (a == null) // but see note below
...but note the latter will also be true if a is undefined.
Is it undefined:
if (typeof a === "undefined")
// o...
Programming with white text on black background?
Does anyone program with white text against black background? I have heard some rumors that it is better for your eyes. What's the case? Is it any better than the traditional black on white? What are the pros and cons?
...
What are the barriers to understanding pointers and what can be done to overcome them? [closed]
...s is a concept that for many can be confusing at first, in particular when it comes to copying pointer values around and still referencing the same memory block.
I've found that the best analogy is to consider the pointer as a piece of paper with a house address on it, and the memory block it refer...
Why is it Valid to Concatenate Null Strings but not to Call “null.ToString()”?
...ions,the C# compiler treats a null string the same as an empty string, but it does not convert the value of the original null string.
More information on the + binary operator:
The binary + operator performs string concatenation when one or both operands are of type string.
If an operand of string...
What is NSLayoutConstraint “UIView-Encapsulated-Layout-Height” and how should I go about forcing it
I have a UITableView running under iOS 8 and I'm using automatic cell heights from constraints in a storyboard.
17 Answer...
Good examples of MVVM Template
I am currently working with the Microsoft MVVM template and find the lack of detailed examples frustrating. The included ContactBook example shows very little Command handling and the only other example I've found is from an MSDN Magazine article where the concepts are similar but uses a slightly d...
What does “use strict” do in JavaScript, and what is the reasoning behind it?
...cently, I ran some of my JavaScript code through Crockford's JSLint , and it gave the following error:
28 Answers
...
Does Javascript pass by reference? [duplicate]
...arts . I am very confused about my parameter for the rectangle function. It is actually undefined , and redefined inside the function. There are no original reference. If I remove it from the function parameter, the inside area function is not able to access it.
...
deciding among subprocess, multiprocessing, and thread in Python?
I'd like to parallelize my Python program so that it can make use of multiple processors on the machine that it runs on. My parallelization is very simple, in that all the parallel "threads" of the program are independent and write their output to separate files. I don't need the threads to exchan...