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搭建高可用mongodb集群（四）—— 分片 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...高可用的mongodb集群：
首先确定各个组件的数量，mongos 3个， config server 3个，数据分3片 shard server 3个，每个shard 有一个副本一个仲裁也就是 3 * 2 = 6 个，总共需要部署15个实例。这些实例可以部署在独立机器也可以部署在一台机...
How to calculate the number of occurrence of a given character in each row of a column of strings?
...
13 Answers
13
Active
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Correct way to convert size in bytes to KB, MB, GB in JavaScript
...tBytes(1024); // 1 KB
formatBytes('1024'); // 1 KB
formatBytes(1234); // 1.21 KB
formatBytes(1234, 3); // 1.205 KB
Demo / source :
function formatBytes(bytes, decimals = 2) {
if (bytes === 0) return '0 Bytes';
const k = 1024;
const dm = decimals < 0 ? 0 ...
List of installed gems?
... >> Platform 0.4.0
# >> abstract 1.0.0
# >> actionmailer 3.0.5
# >> actionpack 3.0.5
# >> activemodel 3.0.5
# >> activerecord 3.0.5
Here's an updated way to get a list:
require 'rubygems'
def local_gems
Gem::Specification.sort_by{ |g| [g.name.downcase, g....
Cost of len() function
...
360
It's O(1) (constant time, not depending of actual length of the element - very fast) on every ...
IIS7 deployment - duplicate 'system.web.extensions/scripting/scriptResourceHandler' section
On attempting to deploy a .net 3.5 website on the default app pool in IIS7 having the framework section set to 4.0, I get the following error.
...
Find nearest value in numpy array
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531
import numpy as np
def find_nearest(array, value):
array = np.asarray(array)
idx = (np....
Convert column classes in data.table
...rter)]
str(dtnew)
Classes ‘data.table’ and 'data.frame': 10 obs. of 3 variables:
$ ID : Factor w/ 2 levels "A","B": 1 1 1 1 1 2 2 2 2 2
$ Quarter: chr "1" "2" "3" "4" ...
$ value : num -0.838 0.146 -1.059 -1.197 0.282 ...
Using lapply and as.character:
dtnew <- dt[, lapply(....
How do you detect where two line segments intersect? [closed]
...ntersect.
Credit: this method is the 2-dimensional specialization of the 3D line intersection algorithm from the article "Intersection of two lines in three-space" by Ronald Goldman, published in Graphics Gems, page 304. In three dimensions, the usual case is that the lines are skew (neither paral...
Python Infinity - Any caveats?
...*2
4.0
>>> _**2
16.0
>>> _**2
256.0
>>> _**2
65536.0
>>> _**2
4294967296.0
>>> _**2
1.8446744073709552e+19
>>> _**2
3.4028236692093846e+38
>>> _**2
1.157920892373162e+77
>>> _**2
1.3407807929942597e+154
>>> _**2
Traceba...