内容简介:Take a look at this small, typical code snippet:I call this theThis is better for lots of reasons:
Take a look at this small, typical code snippet:
let car_ids = []; for (let i = 1; i <= 5; i++) { const car_id = `car-${i}`; if (car_is_empty(car_id)) { car_ids.push(car_id); } } return car_ids;
I call this the iterate-and-mutate pattern. It comes up all the time in code. But every time we see it, we should think about replacing it with a mapping operation, like this: (Ruby syntax)
return (1..5) .map{|n| "car-#{n}"} .select{|m| car_is_empty(m)}
This is better for lots of reasons:
- Code that mutates (changes) a variable is harder to reason about, and so easier to get wrong .
- An explicit for loop is another common source of bugs.
- The original snippet is longer because it’s doing boring, low-level work. More, boring, code is another source of bugs.
- Long code with low-level operations like for loops and push ing values onto arrays is not expressive .
- The shorter, functional version has no variables, no mutation, and no explicit looping. It’s much shorter and easy to understand, once you’ve seen this style.
Here’s a great intro to functional programming in Javascript.
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程序员的自我修养
俞甲子、石凡、潘爱民 / 电子工业出版社 / 2009-4 / 65.00
这本书主要介绍系统软件的运行机制和原理,涉及在Windows和Linux两个系统平台上,一个应用程序在编译、链接和运行时刻所发生的各种事项,包括:代码指令是如何保存的,库文件如何与应用程序代码静态链接,应用程序如何被装载到内存中并开始运行,动态链接如何实现,C/C++运行库的工作原理,以及操作系统提供的系统服务是如何被调用的。每个技术专题都配备了大量图、表和代码实例,力求将复杂的机制以简洁的形式表......一起来看看 《程序员的自我修养》 这本书的介绍吧!