從測試中學習 Go 語言 (迴圈迭代篇)

nofear195 included in Go

2024-02-18 2024-02-19 About 300 words One minute - views - comments

Contents

Iteration

go 語法沒有 do , while 等關鍵字，所有的迴圈迭代只能用 for 去實現

For loop

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for initialization; condition; increment {
    // Code to execute repeatedly
}

for i := 0; i < 5; i++ {
  fmt.Println(i)
}

While loop

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for condition {
    // Code to execute repeatedly
}

i := 0
for i < 5 {
    fmt.Println(i)
    i++
}

Example

repeat_test.go

撰寫 Test function 與 Benchmark function

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package repeat

import "testing"

func TestRepeat(t *testing.T) {
  repeated := Repeat("a")
  expected := "aaaaa"

  if repeated != expected {
    t.Errorf("expected %q but got %q", expected, repeated)
  }
}

func BenchmarkRepeat(b *testing.B) {
  for i := 0; i < b.N; i++ {
    Repeat("a")
  }
}

repeat.go

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package repeat

const repeatCount = 5

func Repeat(character string) string {
  var repeated string
  for i := 0; i < repeatCount; i++ {
    repeated += character
  }
  return repeated
}

test result

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vscode ➜ /workspaces/learn-go/repeat $ go test -v
=== RUN   TestRepeat
--- PASS: TestRepeat (0.00s)
PASS
ok      test-with-go/repeat  0.002s


vscode ➜ /workspaces/learn-go/repeat $ go test -bench .
goos: linux
goarch: arm64
pkg: test-with-go/repeat
BenchmarkRepeat-8       13891360                86.05 ns/op
PASS
ok      test-with-go/repeat  1.288s

Reference

https://quii.gitbook.io/learn-go-with-tests/