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cartesian product in pandas
...n unused column name, then add dummy columns with that name, merge, and finally drop the column on the result? Creating, as opposed to reading, data with pandas is just a pain
– Bananach
Oct 10 '19 at 7:31
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How to check if all of the following items are in a list?
...
Operators like <= in Python are generally not overriden to mean something significantly different than "less than or equal to". It's unusual for the standard library does this--it smells like legacy API to me.
Use the equivalent and more clearly-named method, ...
Modifying location.hash without page scrolling
...reated and placed at the current location of the scroll. It's the same visually as position:fixed/top:0. Thus the scrollbar is "moved" to the exact same spot it currently is on.
– Borgar
Sep 29 '09 at 0:44
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How to check if a table exists in a given schema
... (like OIDs) gets lost in translation from the system catalogs - which actually carry all information.
System catalogs
Your question was:
How to check whether a table exists?
SELECT EXISTS (
SELECT FROM pg_catalog.pg_class c
JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHE...
C++实现一款简单完整的聊天室服务器+客户端 - C/C++ - 清泛网 - 专注C/C++及内核技术
...从缓冲区中取出消息
MessageBuffer.h
//MessageBuffer.h
#ifndef _MESSAGE_BUF_INCLUDE_
#define _MESSAGE_BUF_INCLUDE_
#include <pthread.h>
#define MESSAGE_COUNT 16
#define MESSAGE_LENGTH 2048
class MessageBuffer{
private:
pthread_mutex_t mutex;//访问缓冲的互斥量
pthread_...
How to fix the “java.security.cert.CertificateException: No subject alternative names present” error
...ager that does not validate certificate chains
TrustManager[] trustAllCerts = new TrustManager[] {new X509TrustManager() {
public java.security.cert.X509Certificate[] getAcceptedIssuers() {
return null;
}
public void checkClientTrusted(X509...
Compiling with cython and mingw produces gcc: error: unrecognized command line option '-mno-cygwin'
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It sounds like GCC 4.7.0 has finally removed the deprecated -mno-cygwin option, but distutils has not yet caught up with it. Either install a slightly older version of MinGW, or edit distutils\cygwinccompiler.py in your Python directory to remove all instan...
What is the easiest way to parse an INI file in Java?
...port java.util.regex.Pattern;
public class IniFile {
private Pattern _section = Pattern.compile( "\\s*\\[([^]]*)\\]\\s*" );
private Pattern _keyValue = Pattern.compile( "\\s*([^=]*)=(.*)" );
private Map< String,
Map< String,
String >> _entries = new HashMap...
Localization of DisplayNameAttribute
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I looked all over before finding this page... this is such a life saver. Thanks! Works good on MVC5 for me.
– Kris
Apr 20 '18 at 14:42
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How to correctly implement custom iterators and const_iterators?
...e, std::iterator with random_access_iterator_tag.These base classes define all type definitions required by STL and do other work.
To avoid code duplication iterator class should be a template class and be parametrized by "value type", "pointer type", "reference type" or all of them (depends on impl...