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Slicing of a NumPy 2d array, or how do I extract an mxm submatrix from an nxn array (n>m)?
...ce a NumPy nxn array. I want to extract an arbitrary selection of m rows and columns of that array (i.e. without any pattern in the numbers of rows/columns), making it a new, mxm array. For this example let us say the array is 4x4 and I want to extract a 2x2 array from it.
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How can I multiply and divide using only bit shifting and adding?
How can I multiply and divide using only bit shifting and adding?
14 Answers
14
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Repeat String - Javascript
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Note to new readers: This answer is old and and not terribly practical - it's just "clever" because it uses Array stuff to get
String things done. When I wrote "less process" I definitely meant
"less code" because, as others have noted in subsequent answers, it...
Why does Lua have no “continue” statement?
I have been dealing a lot with Lua in the past few months, and I really like most of the features but I'm still missing something among those:
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Fundamental difference between Hashing and Encryption algorithms
I see a lot of confusion between hashes and encryption algorithms and I would like to hear some more expert advice about:
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Design patterns or best practices for shell scripts [closed]
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I wrote quite complex shell scripts and my first suggestion is "don't". The reason is that is fairly easy to make a small mistake that hinders your script, or even make it dangerous.
That said, I don't have other resources to pass you but my personal experienc...
Approximate cost to access various caches and main memory?
Can anyone give me the approximate time (in nanoseconds) to access L1, L2 and L3 caches, as well as main memory on Intel i7 processors?
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What's the difference between Task.Start/Wait and Async/Await?
...g something
You are.
what is the difference between doing Task.Wait and await task?
You order your lunch from the waiter at the restaurant. A moment after giving your order, a friend walks in and sits down next to you and starts a conversation. Now you have two choices. You can ignore your ...
Get a specific bit from byte
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Easy. Use a bitwise AND to compare your number with the value 2^bitNumber, which can be cheaply calculated by bit-shifting.
//your black magic
var bit = (b & (1 << bitNumber-1)) != 0;
EDIT: To add a little more detail because there ...
Why is a boolean 1 byte and not 1 bit of size?
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Actually, the four x86 instructions bt, bts, btr and btc can address single bits!
– fredoverflow
Jan 7 '11 at 16:07
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