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Express.js: how to get remote client address
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If you are running behind a proxy like NGiNX or what have you, only then you should check for 'x-forwarded-for':
var ip = req.headers['x-forwarded-for'] || req.connection.remoteAddress;
If the proxy isn't 'yours', I wouldn't trust the 'x-forwarded-for' ...
Can Python print a function definition?
...tsource(re.compile)
def compile(pattern, flags=0):
"Compile a regular expression pattern, returning a pattern object."
return _compile(pattern, flags)
This will work in the interactive prompt, but apparently only on objects that are imported (not objects defined within the interactive pro...
Is there a standard sign function (signum, sgn) in C/C++?
...u need to promote and then narrow again. This is branchless and optimizes excellently
Standards-compliant! The bitshift hack is neat, but only works for some bit representations, and doesn't work when you have an unsigned type. It could be provided as a manual specialization when appropriate.
Accura...
How does python numpy.where() work?
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How do they achieve internally that you are able to pass something like x > 5 into a method?
The short answer is that they don't.
Any sort of logical operation on a numpy array returns a boolean array. (i.e. __gt__, __lt__, etc all return boolean arrays where the given condition is true).
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Reduce, fold or scan (Left/Right)?
...ach 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.
reduceLeft and reduceRight cumulate a single result.
foldLeft and foldRight cumulate a single result using a start value.
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Representing and solving a maze given an image
...y), adjusting weights for the colors so that final grayscale image is approximately uniform. You can do it simply by controlling sliders in Photoshop in Image -> Adjustments -> Black & White.
Convert image to binary by setting appropriate threshold in Photoshop in Image -> Adjustments -...
John Carmack's Unusual Fast Inverse Square Root (Quake III)
...uake III source code which calculates the inverse square root of a float, 4x faster than regular (float)(1.0/sqrt(x)) , including a strange 0x5f3759df constant. See the code below. Can someone explain line by line what exactly is going on here and why this works so much faster than the regular im...
data.table vs dplyr: can one do something well the other can't or does poorly?
..., not so much with dplyr . I've read through some dplyr vignettes and examples that have popped up on SO, and so far my conclusions are that:
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Force the origin to start at 0
How can I set the origin / interception of the y-axis and x-axis in ggplot2?
3 Answers
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c++ 写日志通用类，可设置日志级别 - C/C++ - 清泛网 - 专注C/C++及内核技术
...志通用类，可设置日志级别c++ 写日志通用类（windows & linux 通用），可设置日志级别。代码经过较长时间的测试，可用性高。Logger.h
#ifndef __LOGGER_H_
#define __LOGGER_H_
#include <iostream>
#include <atlstr.h>
#pragma warning(disable:4996)
#defi...