A lot of computations involve processing a string one character at a time. Often they start at the beginning, select each character in turn, do something to it, and continue until the end. The pattern of processing is called traversal. One way to wri…

8.1 A string is a sequenceA string is a sequence of characters. You can access the characters one at a time with the bracket operator: >>> fruit = 'banana' >>> letter = fruit[1] The second statement selects character number 1 from fruit…

目录 8.1 字符串是一个序列(A string is a sequence) 8.2 len 8.3 用一个 for 循环进行遍历(Traversal with a for loop) 8.4 字符串切片(String slices) 8.5 字符串是不可变的(Strings are immutable) 8.6 搜索(Searching) 8.7 循环和计数(Looping and counting) 8.8 字符串方法(String methods) 8.9 in 运算符(The in o…

Atitit  循环(loop), 递归(recursion), 遍历(traversal), 迭代(iterate). 1.1. 循环算是最基础的概念, 凡是重复执行一段代码, 都可以称之为循环. 大部分的递归, 遍历, 迭代, 都是循环.1 1.2. 递归的定义是, 根据一种(几种)基本情况定义的算法, 其他复杂情况都可以被逐步还原为基本情况.1 1.3. 递归的基本概念和特点1 1.4. 迭代(数学): 在循环的基础上, 每一次循环, 都比上一次更为接近结果.2 1.5. 编程语言中的循环…

表示“重复”这个含义的词有很多, 比如循环(loop), 递归(recursion), 遍历(traversal), 迭代(iterate). 循环算是最基础的概念, 凡是重复执行一段代码, 都可以称之为循环. 大部分的递归, 遍历, 迭代, 都是循环. 递归的定义是, 根据一种(几种)基本情况定义的算法, 其他复杂情况都可以被逐步还原为基本情况. 在编程中的特征就是, 在函数定义内重复调用该函数. 例如斐波那契数列, 定义F(0)=1, F(1)=1, 所有其他情况: F(x)=F(x-1)+…

表示“重复”这个含义的词有很多, 比如循环(loop), 递归(recursion), 遍历(traversal), 迭代(iterate). 循环算是最基础的概念, 凡是重复执行一段代码, 都可以称之为循环. 大部分的递归, 遍历, 迭代, 都是循环. 递归的定义是, 根据一种(几种)基本情况定义的算法, 其他复杂情况都可以被逐步还原为基本情况. 在编程中的特征就是, 在函数定义内重复调用该函数. 例如斐波那契数列, 定义F(0)=1, F(1)=1, 所有其他情况: F(x)=F(x-1)+…

Given a binary tree, return the preorder traversal of its nodes' values. Given: 1 / \ 2 3 / \ 4 5 return [1,2,4,5,3]. Thinking: For this problem, you need to think about using recursive or non-recursive methods. As recursive method, we should think t…

异步的思考 event loops隐藏得比较深,很多人对它很陌生.但提起异步,相信每个人都知道.异步背后的“靠山”就是event loops.这里的异步准确的说应该叫浏览器的event loops或者说是javaScript运行环境的event loops,因为ECMAScript中没有event loops,event loops是在HTML Standard定义的. event loops规范中定义了浏览器何时进行渲染更新,了解它有助于性能优化. 思考下边的代码运行顺序: console.l…

浏览器组成 User interface: a. Every part of the browser display, except the window. b. The address bar, back/forward button, bookmarking menu, etc. Browser Engine: marshals actions between the UI and the rendering engine. This provides a high-level interf…

Don't Block the Event Loop (or the Worker Pool) | Node.js https://nodejs.org/en/docs/guides/dont-block-the-event-loop/ Don't Block the Event Loop (or the Worker Pool) Should you read this guide? If you're writing anything more complicated than a brie…