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How to find list intersection?
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If order is not important and you don't need to worry about duplicates then you can use set intersection:
>>> a = [1,2,3,4,5]
>>> b = [1,3,5,6]
>>> list(set(a) & set(b))
[1, 3, 5]
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In Python, what is the difference between “.append()” and “+= []”?
...d will add one item to the list, while += will copy all elements of right-hand-side list into the left-hand-side list.
Update: perf analysis
Comparing bytecodes we can assume that append version wastes cycles in LOAD_ATTR + CALL_FUNCTION, and += version -- in BUILD_LIST. Apparently BUILD_LIST outw...
How do I move an existing Git submodule within a Git repository?
...ules:
Since git 1.8.5, git mv old/submod new/submod works as expected and does all the plumbing for you. You might want to use git 1.9.3 or newer, because it includes fixes for submodule moving.
The process is similar to how you'd remove a submodule (see How do I remove a submodule?):
Edi...
What is the difference between ManualResetEvent and AutoResetEvent in .NET?
I have read the documentation on this and I think I understand. An AutoResetEvent resets when the code passes through event.WaitOne() , but a ManualResetEvent does not.
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&& (AND) and || (OR) in IF statements
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No, it will not be evaluated. And this is very useful. For example, if you need to test whether a String is not null or empty, you can write:
if (str != null && !str.isEmpty()) {
doSomethingWith(str.charAt(0));
}
or, the other way around
if ...
Why is TypedReference behind the scenes? It's so fast and safe… almost magical!
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Short answer: portability.
While __arglist, __makeref, and __refvalue are language extensions and are undocumented in the C# Language Specification, the constructs used to implement them under the hood (vararg calling convention, TypedReference type, arglist, refanytype, mkanyref...
“CAUTION: provisional headers are shown” in Chrome debugger
...r Latest Versions of chrome
Type chrome://net-export/ in the address bar and hit enter.
Start Recording. And save Recording file to local.
Open the page that is showing problems.
Go back to net-internals
You can view Recorded Log file Here https://netlog-viewer.appspot.com/#import
click on events ...
How to define a two-dimensional array?
...sion that could arise with the indexing, if you use "x" for both the inner and outer lists, and want a non-square Matrix.
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How do you remove duplicates from a list whilst preserving order?
...o seen_add instead of just calling seen.add? Python is a dynamic language, and resolving seen.add each iteration is more costly than resolving a local variable. seen.add could have changed between iterations, and the runtime isn't smart enough to rule that out. To play it safe, it has to check the o...
Singleton pattern in nodejs - is it needed?
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This has basically to do with nodejs caching. Plain and simple.
https://nodejs.org/api/modules.html#modules_caching
(v 6.3.1)
Caching
Modules are cached after the first time they are loaded. This means
(among other things) that every call to require('foo') will ge...