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# System prepended metadata

title: 第3次 Learn go with tests 讀書會預習筆記

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# 第3次 Learn go with tests 讀書會預習筆記

2023/11/08(三) 20:30
教材：
英文 [Iteration - learn-go-with-tests](https://quii.gitbook.io/learn-go-with-tests/go-fundamentals/iteration)
中文 [Iteration - learn-go-with-tests](https://studygolang.gitbook.io/learn-go-with-tests/go-ji-chu/iteration)
Discord 語音頻道: https://discord.com/channels/1119319218354135060/1157349998393049088

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## 提問區

* 
* 

## 筆記區

1. 用 for 關鍵字, 寫了Repeat函式功能, 又再次介紹了一次TDD的週期(感覺是讓閱讀的人熟悉)
```
TDD週期
(1) Write a test
(2) Make the compiler pass
(3) Run the test, see that it fails and check the error (4) message is meaningful
(5) Write enough code to make the test pass
(6) Refactor
```

2. 介紹 go test -bench 功能
* `go test -bench=.` is a go test benchmark feature
* example case:
```go
func BenchmarkRepeat(b *testing.B) {
	for i := 0; i < b.N; i++ {
		Repeat("a", 6)
	}
}

// cpu: Intel(R) Core(TM) i5-10400F CPU @ 2.90GHz
// BenchmarkRepeat-12       8243114               129.4 ns/op
// PASS
// ok      gotest/iteration        1.217s
```
output 意思是共花了 1.217 秒執行了 Repeat函式共 8243114次

3. 文章最下方練習建議從 go std 裡面找函式出來練習, 我找了 strings.Contains 來撰寫簡單測試, 並且把前面章節的 godoc以及 -bench 功能都寫上

4. code 分享區的連結, 裡面以下 pkg
- Repeat
- Contains
- Leetcode98 valid binary search tree

## Code 分享區 （可貼replit、 GitHub gist等連結）

* [Repeat / Contains / LeetCode98 程式碼範例](https://replit.com/@yale918/LeetCode-Go-98-ValidateBinarySearchTree#main.go)


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## 附註

* 使用 vscode 進行
* 此筆記版型參考 Jack Hung 大大, 有經過本人同意, 並謝謝 Jack大大不吝分享
