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PHP check whether property exists in object or class
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property_exists( mixed $class , string $property )
if (property_exists($ob, 'a'))
isset( mixed $var [, mixed $... ] )
if (isset($ob->a))
isset() will return false if property is null
Example 1:
$ob->a = null
var_dump(isset($ob->a)); // false
Example 2: ...
How to filter array in subdocument with MongoDB [duplicate]
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Does the aggregation operation modify the document or does it just perform a selection ?
– Cherif
Oct 27 '13 at 22:18
3
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MFC 日期时间控件CDateTimeCtrl自绘 - C/C++ - 清泛网 - 专注C/C++及内核技术
...nclude "stdafx.h"
#include "MyDateTime.h"
#include "../CommonFunc.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
CMyDateTime::CMyDateTime()
{
m_nIDLeft = m_nIDRight = m_nIDCenter = 0;
//m_nIDListLeft, m_nIDListRight, m_nIDListTop, ...
Variable interpolation in the shell
...h}_newstap.sh
or
$filepath\_newstap.sh
_ is a valid character in identifiers. Dot is not, so the shell tried to interpolate $filepath_newstap.
You can use set -u to make the shell exit with an error when you reference an undefined variable.
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PSQLException: current transaction is aborted, commands ignored until end of transaction block
...tarted using Postgres... it's really annoying that Postgres does this, and now we have to be really rewrite a big bulk of our program that we are porting from Oracle to Postgres. Why isn't there an option like the first to make it behave like Oracle but without the auto-commit?
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Hidden Features of Java
...d it, never heard of it before.
ThreadLocals are typically not so widely known as a way to store per-thread state.
Since JDK 1.5 Java has had extremely well implemented and robust concurrency tools beyond just locks, they live in java.util.concurrent and a specifically interesting example is the j...
oracle10g 网址收藏 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
...indows (32-bit)
http://download.oracle.com/otn/nt/oracle10g/10201/10201_database_win32.zip
http://download.oracle.com/otn/nt/oracle10g/10201/10201_client_win32.zip
http://download.oracle.com/otn/nt/oracle10g/10201/10201_clusterware_win32.zip
http://download.oracle.com/otn/nt/oracle10g/1020...
oracle10g 网址收藏 - ORACLE - 清泛IT论坛，有思想、有深度
...t Windows (32-bit)
http://download.oracle.com/otn/nt/oracle10g/10201/10201_database_win32.zip
http://download.oracle.com/otn/nt/oracle10g/10201/10201_client_win32.zip
http://download.oracle.com/otn/nt/oracle10g/10201/10201_clusterware_win32.zip
http://download.oracle.com/otn/nt/oracle10g/10201/1...
Convert a row of a data frame to vector
...tly more explicit way to get to the same result.
As @Josh comments below, if you have a not-completely-numeric (alphabetic, factor, mixed ...) data frame, you need as.character(df[1,]) instead.
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urlencode vs rawurlencode?
If I want to create a URL using a variable I have two choices to encode the string. urlencode() and rawurlencode() .
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