ARTS打卡 - 20191007~20191013

Published: October 07, 2019 by Forrest Yang

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ARTS打卡 6

这个系列是 ARTS 打卡计划，什么是ARTS，参看这里 https://time.geekbang.org/column/article/85839

Algorithm

Review

本次点评Go官网的一篇关于反射的文章 https://blog.golang.org/laws-of-reflection 。

Because reflection builds on the type system, let's start with a refresher about types in Go.

Go is statically typed. Every variable has a static type, that is, exactly one type known and fixed at compile time: int, float32, *MyType, []byte, and so on. If we declare
type MyInt int

var i int
var j MyInt
then i has type int and j has type MyInt. The variables i and j have distinct static types and, although they have the same underlying type, they cannot be assigned to one another without a conversion.

理解Go的类型系统(type system)非常重要，原文中i和j有不同的static type，相同的underlying type，并不能把一个直接赋值给另一个，而需要强制类型转换。

Here again are the laws of reflection:

Reflection goes from interface value to reflection object.

Reflection goes from reflection object to interface value.

To modify a reflection object, the value must be settable.

Once you understand these laws reflection in Go becomes much easier to use, although it remains subtle. It's a powerful tool that should be used with care and avoided unless strictly necessary.

应用反射的几个法则：

反射能将interface转化为反射对象
反射能将反射对象转化为interface
如果要修改一个反射对象，前提是它的value是可以改变的(settable)。

在实际应用中，往往还要有实际数据类型(int, float, struct等)跟interface的转化。

最终转化规则可以概括为反射对象 <=> interface <=> static type。

Tip

最近开始用Go语言在LeetCode刷题，有个小技巧，用for i := 0 …… i ++代替for …… range来遍历slice，避免了循环中值拷贝，在基础测试中有时能更胜一筹。在一道数组题的解答中，分别了用两种方法提交了两次，运行时击败人数提高了25%！

Go 语言陷阱(一)

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