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How to clone a case class instance and change just one field in Scala?
...ed on current value.
val newPersona2 = messageLens.modify(existingPersona)(_ + "iPad")
// Results:
// newPersona1: Persona(store,apple,Set())
// newPersona2: Persona(store,apple,Set(iPhone, iPad))
Moreover, in case you have nested case classes, the getter and setter methods can be a bit tedious t...
In Python, how can you load YAML mappings as OrderedDicts?
...
Update: In python 3.6+ you probably don't need OrderedDict at all due to the new dict implementation that has been in use in pypy for some time (although considered CPython implementation detail for now).
Update: In python 3.7+, the insertion-order preservation nature of dict objects h...
How can I efficiently select a Standard Library container in C++11?
...ecause list is not such a good container in general, and neither is forward_list. Both lists are very specialized containers for niche applications.
To build such a chart, you just need two simple guidelines:
Choose for semantics first
When several choices are available, go for the simplest
Wor...
.NET HttpClient. How to POST string value?
...
You should private static readonly HttpClient _client = new HttpClient(); instead aspnetmonsters.com/2016/08/2016-08-27-httpclientwrong
– Sameer Alibhai
May 9 '17 at 15:05
...
How to convert wstring into string?
...e <locale>
#include <vector>
int main() {
std::setlocale(LC_ALL, "");
const std::wstring ws = L"ħëłlö";
const std::locale locale("");
typedef std::codecvt<wchar_t, char, std::mbstate_t> converter_type;
const converter_type& converter = std::use_facet<converter...
What's the difference between libev and libevent?
... each of these, by not using global variables but using a loop context for all functions, by using small watchers for each event type (an I/O watcher uses 56 bytes on x86_64 compared to 136 for libevent), allowing extra event types such as timers based on wallclock vs. monotonic time, inter-thread i...
Git command to show which specific files are ignored by .gitignore
...kes a file to be ignored in your git repo.
On Unix, using "What expands to all files in current directory recursively?" and a bash4+:
git check-ignore **/*
(or a find -exec command)
Note: https://stackoverflow.com/users/351947/Rafi B. suggests in the comments to avoid the (risky) globstar:
git ...
Converting strings to floats in a DataFrame
...newer version of pandas (0.17 and up), you can use to_numeric function. It allows you to convert the whole dataframe or just individual columns. It also gives you an ability to select how to treat stuff that can't be converted to numeric values:
import pandas as pd
s = pd.Series(['1.0', '2', -3])
p...
线程访问窗口资源的问题 - C/C++ - 清泛网 - 专注C/C++及内核技术
...并行运行的窗口）。在工作线程里调用AfxGetMainWnd（）->m_hWnd出错，也会发生发生内存访问冲突。（AfxGetMainWnd得到的是当前线程的主窗口）。
2.ASSERT((p = pMap->LookupPermanent(m_hWnd)) != NULL ||
(p = pMap->LookupTemporary(m_hWnd)) != NULL)失败;从...
How to pass a function as a parameter in Java? [duplicate]
...u have a class or interface with only a single abstract method (sometimes called a SAM type), for example:
public interface MyInterface {
String doSomething(int param1, String param2);
}
then anywhere where MyInterface is used, you can substitute a lambda expression:
class MyClass {
publ...