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Reduce, fold or scan (Left/Right)?
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In general, all 6 fold functions apply a binary operator to each element of a collection. The result of each step is passed on to the next step (as input to one of the binary operator's two arguments). This way we can cumulate a result.
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What's the point of const pointers?
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"Help the compiler help you" is the mantra I normally chant for this.
– Flexo♦
Oct 11 '11 at 9:44
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Deep null checking, is there a better way?
...'d say
cake?.frosting?.berries?.loader
and the compiler would generate all the short-circuiting checks for you.
It didn't make the bar for C# 4. Perhaps for a hypothetical future version of the language.
Update (2014):
The ?. operator is now planned for the next Roslyn compiler release. Note ...
What does the “map” method do in Ruby?
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Ahhh I get it. So .map actually mutates the array while .each just loops through the array to access the values while leaving the original array untouched?
– bigpotato
Aug 23 '12 at 4:18
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Perform an action in every sub-directory using Bash
... command, this is more concise:
for D in *; do [ -d "${D}" ] && my_command; done
Or an even more concise version (thanks @enzotib). Note that in this version each value of D will have a trailing slash:
for D in */; do my_command; done
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Simple example of threading in C++
...ill execute, followed by the function's parameters. The thread is automatically started upon construction.
If later on you want to wait for the thread to be done executing the function, call:
t1.join();
(Joining means that the thread who invoked the new thread will wait for the new thread to fi...
How do I manage MongoDB connections in a Node.js web application?
...there are multiple database.. should i open a connection for each database all together. If not, Is it OK to open and close when required?
– Aman Gupta
Oct 25 '16 at 14:19
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Convert light frequency to RGB?
...teachers may have told us (well mine did). Too bad, but in practice not usually fatal.
– Francis Davey
May 29 '10 at 22:58
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How to convert an array of strings to an array of floats in numpy?
...(or equivalently, use a list comprehension). (In Python 3, you'll need to call list on the map return value if you use map, since map returns an iterator now.)
However, if it's already a numpy array of strings, there's a better way. Use astype().
import numpy as np
x = np.array(['1.1', '2.2', '3....
Can you split a stream into two streams?
... @JoD It is thread-safe if heads and tails are thread-safe. Additionally, assuming the use of non-parallel streams, only the order is not guaranteed, so they are thread-safe. It's up to the programmer to fix concurrency issues, so this answer is perfectly suitable if the collections are threa...