match. a type:
\d: number \w: [a-z] [0-9_] \s: any whitespace .: match any charcter., except for \n match times:
?: [0,1] +:[1, +unlimited] : [0, +unlimited] 2. syntax base single char quantifiers(数量) position(位置) \d 匹配数字 * 0个或者更多 ^一行的开头 \w 匹配word(数字、字母) + 1个或更多，至少1个 $一行的结尾 \W 匹配非word(数字、字母) ? 0个或1个,一个Optional \b 单词"结界"(word bounds) \s 匹配white space(包括空格、tab等) {min,max}出现次数在一个范围内 \S 匹配非white space(包括空格、tab等) {n}匹配出现n次的 . 匹配任何，任何的字符 1. character class(character set) 1 The lynk is quite a link don't you think?
声明文件
what is type script add type system on top layer of js;
for primitive Data for compound Data use interface to describe tyep
1 2 3 4 5 6 7 8 9 interface User { name: string; id: number; } // option properties interface SquareConfig { color?: string; width?: number; } use interface as a function type 1 2 3 4 5 6 7 8 9 interface SearchFunc { (source: string, subString: string): boolean; } let mySearch: SearchFunc; mySearch = function (source: string, subString: string) { let result = source.
go操作etcd
what distributed key-value store:
strongly consistently use raft vs redis: same: key value store
differ:
使用场景： redis: 存储业务数据,快速 etcd: 存储关键数据, 可靠 arhitecture: componetnt:
grpc server raft algorithm store: wal boltdbd: key value storeage basic operation 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 #set etcdctl put a b # get etcdclt get a etcdctl get "" --prefix // get all keys // read old version etcd get a --rev=5 // the max revision is 5; # expired time etcdctl lease grant 100 etcdctl lease keep-alive leaseid etcdctl put a b --lease leaseid # del etcdctl del a service discovery how:
Go Concurrency Patterns: Context
深度解密Go语言之context
context what: 可以理解为一个特殊的局部变量；
存取变量是 线程安全； 可以传递阻塞/取消信号； 使用场景: 需要在多个协程里传递变量，信号；
举例说明:
api handle: context: cancel a batch of g; pass value to specify-scoped of g; channel： share data between g select： receive/send data from/to mutiple channel;
cancel or pass data;
what: go 提供的线程安全的共享信号和变量
相比全局变量：
block a group of goroutine thread safe 1 2 3 4 5 6 7 8 9 10 11 type Context interface { Done() <-chan struct{} // return a will be be closed channel; Err() error; Deadline() (deadline time.
Redis 中 HyperLogLog 的使用场景 布隆过滤器（附go语言代码实现，详细注释）
bigdata what’s? 当大量数据产生的时候，传统手段处理起来乏力，需要一些新的手段 bitmap; data Structure bit array;一个
1 2 3 4 5 6 var bitmap []bit ; func (offset){ bit[offset/8] |= offset%8 }; how save space:
int32: 32bit; in bitmap 1bit 32倍 4 billion data:
bitmap: 2^32 * (1/8)/1024/1024 = 512M; normal: 2^32*4/1024/1024 = 512M * 30 = 15G;
usecase:
1 2 setbit ssp_clickcount 111 1; bitCount ssp_clickcount 0 -1; HyperLogLog； 实时数据分析；估算
1 2 PFADD ssp_001 PFCount 原理：
原型与继承 是什么？ 每个构造函数内部都有一个prototype属性;指向一个原型对象,每个对象实例内部都有一个prototype属性，指向同一个原型对象。 1 2 3 function Person() {} let person1 = new Person(); person1.__proto__ == Person.prototype; 通过改变构造函数指向的原型对象，来构造继承关系
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 function SuperType(){ this.Propertype = true; } SuperType.prototype.getSuperValue = function(){ return this.Propertype; } function SubType() this.Propertype = false; } SubType.prototype = new SuperType(); SubType.prototype.getSubValue = function(){ return this.Propertype; } let sub = new SubType() console.log(sub.getSuperValue());
