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How to check if a specific key is present in a hash or not?
I want to check whether the "user" key is present or not in the session hash. How can I do this?
7 Answers
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Why does X[Y] join of data.tables not allow a full outer join, or a left join?
This is a bit of a philosophical question about data.table join syntax. I am finding more and more uses for data.tables, but still learning...
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Force LF eol in git repo and working copy
...b. Many of the files were initially developed on Windows, and I wasn't too careful about line endings. When I performed the initial commit, I also didn't have any git configuration in place to enforce correct line endings. The upshot is that I have a number of files with CRLF line endings in my gith...
Is async HttpClient from .Net 4.5 a bad choice for intensive load applications?
I recently created a simple application for testing the HTTP call throughput that can be generated in an asynchronous manner vs a classical multithreaded approach.
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Simplest way to do a fire and forget method in c# 4.0
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stl 字符串std::string作为std::map主键key的实例 - C/C++ - 清泛网 - 专注C/C++及内核技术
...法，并使用find_if实现map按value值查找。代码如下：
#include <map>
#include <string>
#include <algorithm>
using namespace std;
class map_value_finder
{
public:
map_value_finder(const std::string &cmp_string):m_s_cmp_string(cmp_string){}
bool operator ()(const std:...
std::string截取字符串，截取ip:port - C/C++ - 清泛网 - 专注C/C++及内核技术
...0.1:8888");int index = ip.find_last_of(':'); 获取ipip.substr(0, index).c_str(); 获取portip.substr(index + 1).c_str();std::string ip("127.0.0.1:8888");
int index = ip.find_last_of(':');
// 获取ip
ip.substr(0, index).c_str();
// 获取port
ip.substr(index + 1).c_str();字符串截取
Linux automake自动编译全攻略 - C/C++ - 清泛网 - 专注C/C++及内核技术
...译配置。
automake流程图示如下：
核心配置如下：
configure.in：
AC_INIT([test], [1.0.0], [bugreport.test.com])
#指定项目名称和版本号
AM_INIT_AUTOMAKE(test, 1.0.0)
#检查编译器
AC_PROG_CC
AC_PROG_LIBTOOL
#输出Makefile文件
AC_CONFIG_FILES(...
[工程源码实例] C++ ADO 读写Excel源码及注意点 - C/C++ - 清泛网 - 专注C/C++及内核技术
[工程源码实例] C++ ADO 读写Excel源码及注意点工程源码下载：excel-ado.zip运行结果截图：生成的Ｅｘｃｅｌ截图：主要代码片段： 导入Excel COM支持。。。不过程序编译后即使客户机没...工程源码下载：excel-ado.zip
运行结果截图：...
error C2662: “Screen::move”: 不能将“this”指针从“const Screen”转...
error C2662: “Screen::move”: 不能将“this”指针从“const Screen”转换为“ Screen &” 转换丢失限定符出错代码： 成员函数定义Screen& Screen::move(index r,index c){ index row = r * width; cursor = row + c;...出错代码：
//成员函数定义
Screen& Scr...