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How update the _id of one MongoDB Document?
...rted with a duplicate value in a unique indexed field. You could fix this by doing the delete first, but that is a bad idea because if your insert fails for some reason your data is now lost. You must instead drop your index, perform the work, then restore the index.
– skelly...
B-Tree vs Hash Table
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You can only access elements by their primary key in a hashtable.
This is faster than with a tree algorithm (O(1) instead of log(n)), but you cannot select ranges (everything in between x and y).
Tree algorithms support this in Log(n) whereas hash indexe...
techniques for obscuring sensitive strings in C++
...ng key with XOR
For instance, you could use XOR to split the key into two byte arrays:
key = key1 XOR key2
If you create key1 with the same byte-length as key you can use (completely) random byte values and then compute key2:
key1[n] = crypto_grade_random_number(0..255)
key2[n] = key[n] XOR key...
Putting text in top left corner of matplotlib plot
...'t want an actual legend. You can specify the placement of the legend box by using the loc keyterm. More information can be found at this website but I've also included an example showing how to place a legend:
ax.scatter(xa,ya, marker='o', s=20, c="lightgreen", alpha=0.9)
ax.scatter(xb,yb, marke...
Constructor in an Interface?
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Couldn't the language have done it by allowing things like class A implements Named, HashList { A(){HashList(new list()); Named("name");} }
– mako
Sep 10 '13 at 23:19
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Can I record/play macros in Visual Studio 2012/2013/2015/2017/2019?
...veloper Preview
I have started to get around this (although inconvenient) by cutting/pasting into Notepad++, record and run the macro there and then cut/paste it back into Visual Studio 2012.
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Is there any way in C# to override a class method with an extension method?
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@Alex by mentioning virtual I am simply clarifying what it means to be polymorphic. In virtually all uses of GetHashCode, the concrete type is unknown - so polymorphism is in play. As such, extension methods wouldn't help even if t...
What does int argc, char *argv[] mean?
...sed to main() in C and C++.
argc will be the number of strings pointed to by argv. This will (in practice) be 1 plus the number of arguments, as virtually all implementations will prepend the name of the program to the array.
The variables are named argc (argument count) and argv (argument vector...
How to list branches that contain a given commit?
... if commit for your favorite open source project that reduces memory usage by 75% is in yet.
$ git log -1 tests
commit d590f2ac0635ec0053c4a7377bd929943d475297
Author: Nick Quaranto <nick@quaran.to>
Date: Wed Apr 1 20:38:59 2009 -0400
Green all around, finally.
$ git branch --contains...
what's data-reactid attribute in html?
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It's a custom html attribute but probably in this case is used by the Facebook React JS Library.
Take a look: http://facebook.github.io/react/
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