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How to remove last n characters from every element in the R vector
...of functions whose names are most consistent and descriptive than those in base R (in fact I always google for "how to get the number of characters in R" as I can't remember the name nchar()).
library(stringr)
str_sub(iris$Species, end=-4)
#or
str_sub(iris$Species, 1, str_length(iris$Species)-3)
...
How to create a self-signed certificate for a domain name for development?
...et 2.0 SDK. On my server it's at:
C:\Program Files\Microsoft.Net\SDK\v2.0 64bit\Bin\makecert.exe
You can create a signing authority and store it in the LocalMachine certificates repository as follows (these commands must be run from an Administrator account or within an elevated command prompt):
...
Using Eloquent ORM in Laravel to perform search of database using LIKE
...
64
If you need to frequently use LIKE, you can simplify the problem a bit. A custom method like ()...
How do I clear a search box with an 'x' in bootstrap 3?
...s intent was to pass a truthy paramter to hide() to start off hidden/shown based on if the input has a value already. If that was the intent, he failed (hide always hides). It should be $(".clearer").toggle(!!$(this).prev('input').val());
– Jeff Shepler
Jun 10 ...
Can C++ code be valid in both C++03 and C++11 but do different things?
....
size_t s = list.size(); // Might be an O(n) operation in C++03
std::ios_base::failure does not derive directly from std::exception anymore
While the direct base-class is new, std::runtime_error is not. Thus:
try {
std::cin >> variable; // exceptions enabled, and error here
} catch(std::...
记一次MongoDB性能问题 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...解决：
MongoDB按需自动生成数据文件：先是<DB>.0，大小是64M，然后是<DB>.1，大小翻番到128M，到了<DB>.5，大小翻番到2G，其后的数据文件就保持在2G大小。为了避免可能出现的问题，可以采用事先手动创建数据文件的策略：
#!/bin...
How to call asynchronous method from synchronous method in C#?
...
Asynchronous programming does "grow" through the code base. It has been compared to a zombie virus. The best solution is to allow it to grow, but sometimes that's not possible.
I have written a few types in my Nito.AsyncEx library for dealing with a partially-asynchronous code b...
Measuring elapsed time with the Time module
...elapsed since the first call to this function, as a floating point number, based on the Win32 function QueryPerformanceCounter(). The resolution is typically better than one microsecond.
Update for Python 3.7
New in Python 3.7 is PEP 564 -- Add new time functions with nanosecond resolution.
Us...
Getting multiple keys of specified value of a generic Dictionary?
... the missing functions to make it an IDictionary compatible class. This is based on the version with unique Key-Value Pairs. Here's the file if desired (Most work was the XMLDoc through):
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;...
How do you configure Django for simple development and deployment?
...ings files.
settings_local.py - host-specific configuration, such as database name, file paths, etc.
settings_development.py - configuration used for development, e.g. DEBUG = True.
settings_production.py - configuration used for production, e.g. SERVER_EMAIL.
I tie these all together with a set...