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How do I manage MongoDB connections in a Node.js web application?
...tive says:
You open do MongoClient.connect once when your app boots up and reuse
the db object. It's not a singleton connection pool each .connect
creates a new connection pool.
So, to answer your question directly, reuse the db object that results from MongoClient.connect(). This gives yo...
Does Java have something like C#'s ref and out keywords?
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No, Java doesn't have something like C#'s ref and out keywords for passing by reference.
You can only pass by value in Java. Even references are passed by value. See Jon Skeet's page about parameter passing in Java for more details.
To do something similar to ref or ou...
Why Func instead of Predicate?
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While Predicate has been introduced at the same time that List<T> and Array<T>, in .net 2.0, the different Func and Action variants come from .net 3.5.
So those Func predicates are used mainly for consistency in the LINQ operators. As of .net 3.5, about using Func<T> and Action...
jQuery append() vs appendChild()
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The main difference is that appendChild is a DOM method and append is a jQuery method. The second one uses the first as you can see on jQuery source code
append: function() {
return this.domManip(arguments, true, function( elem ) {
if ( this.nodeType === 1 || this.nod...
How to check if all of the following items are in a list?
...nificantly different than "less than or equal to". It's unusual for the standard library does this--it smells like legacy API to me.
Use the equivalent and more clearly-named method, set.issubset. Note that you don't need to convert the argument to a set; it'll do that for you if needed.
set(['a...
printf() formatting for hex
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The # part gives you a 0x in the output string. The 0 and the x count against your "8" characters listed in the 08 part. You need to ask for 10 characters if you want it to be the same.
int i = 7;
printf("%#010x\n", i); // gives 0x00000007
printf("0x%08x\n", i); // gives 0x0...
unix - head AND tail of file
Say you have a txt file, what is the command to view the top 10 lines and bottom 10 lines of file simultaneously?
20 Answer...
How to “git show” a merge commit with combined diff output even when every changed file agrees with
...o way to do this with git show. But it would certainly be nice sometimes, and it would probably be relatively easy to implement in the git source code (after all, you just have to tell it to not trim out what it thinks is extraneous output), so the patch to do so would probably be accepted by the g...
How to merge specific files from Git branches
I have 2 git branches branch1 and branch2 and I want to merge file.py in branch2 into file.py in branch1 and only that file.
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LINQ query on a DataTable
I'm trying to perform a LINQ query on a DataTable object and bizarrely I am finding that performing such queries on DataTables is not straightforward. For example:
...