http://stackoverflow.com/questions/793897/check-if-keyvaluepair-exists-with-linqs-firstordefault 问题: I have a dictionary of type Dictionary<Guid,int> I want to return the first instance where a condition is met using var available = m_AvailableDict.…
Sometime you need to check one prop exists on the object and value should not be ´null´ or ´undefined´. One problem people may occur with: const {get} = require('lodash') } const existing = typeof get(obj, 'a') !== undefined // true Here we missed if…
kill -0 pid sending the signal 0 to a given PID just checks if any process with the given PID is running and you have the permission to send a signal to it. $ man 2 kill If sig is 0, then no signal is sent, but error checking is still performed; this…
Restriction Operators Where - Simple public void Linq1() { , , , , , , , , , }; var lowNums = from n in numbers select n; Console.WriteLine("Numbers < 5:"); foreach (var x in lowNums) { Console.WriteLine(x); } } Where - Simple public void Lin…
更多LeetCode解题详解 Easy Given an array arr of integers, check if there exists two integers N and M such that N is the double of M ( i.e. N = 2 * M). More formally check if there exists two indices i and j such that : i != j 0 <= i, j < arr.length arr[i]…
最近抽空做个小工具,使用AWSSDK 对本地文件目录监控,并自动同步上传文件到S3 的过程,使用的是多线程异步上传,针对大文件进行了分块 参考文献: https://www.codeproject.com/Articles/131678/Amazon-S-Sync https://aws.amazon.com/cn/documentation/s3/ Introduction The SprightlySoft S3 Sync application allows you to take a f…
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace CA.TCP { using System.Net; using System.Net.Sockets; using System.Threading; using System.Configuration; class Program { sta…
1.Oracel数据库没有字段自增长属性,要实现自增长通常是通过查询序列或者触发器来实现的. 设置自增长主键 alter table SUB_SUBSCRIPTION add primary key(ID); ) NOT NULL AUTO_INCREMENT; 2.MySQL如何获取行号 MySQL中没有直接获取行号的函数,但是可以自己创建一个函数. -- 创建行号函数 CREATE FUNCTION func_rowNumber() RETURNS int NO SQL NOT DETERM…
Given a set of intervals, for each of the interval i, check if there exists an interval j whose start point is bigger than or equal to the end point of the interval i, which can be called that j is on the "right" of i. For any interval i, you ne…
463. Island Perimeterhttps://leetcode.com/problems/island-perimeter/就是逐一遍历所有的cell,用分离的cell总的的边数减去重叠的边的数目即可.在查找重叠的边的数目的时候有一点小技巧,就是沿着其中两个方向就好,这种题目都有类似的规律,就是可以沿着上三角或者下三角形的方向来做.一刷一次ac,但是还没开始注意codestyle的问题,需要再刷一遍. class Solution { public: int islandPerime…
linux内核的linux-3.6.5\Documentation\kbuild\makefiles.txt Linux Kernel Makefiles This document describes the Linux kernel Makefiles. === Table of Contents === Overview === Who does what === The kbuild files --- 3.1 Goal definitions --- 3.2 Built-in obje…
function dateGetter(name, size, offset, trim) { offset = offset || 0; return function (date) { var value = date['get' + name](); if (offset > 0 || value > -offset) value += offset; if (value === 0 && offset == -12) value = 12; return padNumb…
Given a set of intervals, for each of the interval i, check if there exists an interval j whose start point is bigger than or equal to the end point of the interval i, which can be called that j is on the "right" of i. For any interval i, you ne…
上次一篇“你写的try…catch真的有必要吗”引起了很多朋友的讨论.本次我在code review又发现了一个问题,那就是有人有意无意的写出了return null这样的代码,例如: public User GetUser(Guid userId) { if ( /*for some reason*/) return null; return DB.GetByUserId(userId); } 这样的写法有木有问题? 在我看来没有充分的理由不应该返回null,因为方法的使用者并不知道在何种条件…
B 树(B-Tree)是为磁盘等辅助存取设备设计的一种平衡查找树,它实现了以 O(log n) 时间复杂度执行查找.顺序读取.插入和删除操作.由于 B 树和 B 树的变种在降低磁盘 I/O 操作次数方面表现优异,所以经常用于设计文件系统和数据库. B 树内的节点关系 B 树的定义 B 树的操作 B 树的变种 B+ 树的优势 B+ 树 C# 代码实现 在 1972 年,在 Boeing Research Labs 工作的 Rudolf Bayer 和 Ed McCreight 发明了 B 树.当时…
