查找、解析和验证电子邮件地址

huangapple
go评论116阅读模式
英文:

finding, parsing and validating email addresses

问题

  1. import "fmt"
  3. func main() {
  4.     email := "learning@gmail.com"
  5.     atTrue := false
  6.     s := ""
  7.     domain := ""
  8.     tld := ""
  9.     for i := 0; i < len(email); i++ {
  10.         if atTrue {
  11.             s += string(email[i])
  12.         }
  13.         if string(email[i]) == "@" {
  14.             atTrue = true
  15.         }
  16.         if string(email[i]) == "." {
  17.             atTrue = false
  18.             domain = s
  19.             s = ""
  20.         }
  21.     }
  22.     tld = s
  23.     fmt.Println("Domain:", domain, "and TLD:", tld)
  24. }

当前输出：Domain: gmail and TLD: com

期望输出：Domain: gmail and TLD: com

如何指示从某个字符串到某个字符串的循环？

英文: 
  1.  import &quot;fmt&quot;
  3. func main() {
  4.     email := &quot;learning@gmail.com&quot;
  5.     atTrue := false
  6.     s := &quot;&quot;
  7.     for i := 0; i &lt; len(email); i++ {
  8.         if atTrue {
  9.             s += string(email[i])
  10.         }
  11.         if string(email[i]) == &quot;@&quot; {
  12.             atTrue = true
  13.         }
  14.     }
  15.     fmt.Println(s)
  16. }

current output: gmail.com

expect output: Domain: gmail and TLD: com

How to indicate looping from certain string to certain string?

答案1

得分: 3

使用strings.Split函数

  1. 	email := "learning@gmail.com"
  2. 	split := strings.Split(email, "@")
  3. 	split = strings.Split(split[1], ".")
  4. 	fmt.Println("Domain:", split[0])
  5. 	fmt.Println("TLD:", split[1])

你可以使用mail.ParseAddress函数验证电子邮件字符串

  1. 	email := "learning@gmail.com"
  2. 	addr, err := mail.ParseAddress(email)
  3. 	if err != nil {
  4. 		log.Fatal(err)
  5. 	}

如果TLD是co.id，输出仍然是co.id吗？
尝试找到.的第一个索引（strings.Index），并使用它来分隔字符串

  1. 	email := "learning@gmail.co.id"
  2. 	split := strings.Split(email, "@")
  3. 	index := strings.Index(split[1], ".")
  4. 	fmt.Println("Domain:", split[1][:index])
  5. 	fmt.Println("TLD:", split[1][index+1:])

或者使用regexp.Split函数

  1. 	email := "learning@gmail.co.id"
  2. 	split := strings.Split(email, "@")
  3. 	split = regexp.MustCompile("[.]").
  4. 		Split(split[1], 2)
  5. 	fmt.Println("Domain:", split[0])
  6. 	fmt.Println("TLD:", split[1])

或者使用strings.SplitN

  1.     email := "learning@gmail.co.id"
  2. 	split := strings.Split(email, "@")
  3. 	split = strings.SplitN(split[1], ".", 2)
  4. 	fmt.Println("Domain:", split[0])
  5. 	fmt.Println("TLD:", split[1])

或者使用strings.Cut

  1. 	_, host, found := strings.Cut(email, "@")
  2. 	if !found {
  3. 		t.Fatal("fail cut to host (Domain + TLD)")
  4. 	}
  5. 	domain, tld, found := strings.Cut(host, ".")
  6. 	if !found {
  7. 		t.Fatal("fail cut to Domain and TLD")
  8. 	}
  9. 	fmt.Println("Domain:", domain)
  10. 	fmt.Println("TLD:", tld)

PLAYGROUND

基准测试

  1. 	const (
  2. 		quantity   = 10000
  3. 		userLength = 10
  4. 		domain     = "gmail.com"
  5. 	)
  6. 	var (
  7. 		letterRunes = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
  8. 		emails      = make([]string, 0, quantity)
  9. 		seeded      = rand.New(rand.NewSource(time.Now().UnixMilli()))
  10. 	)
  12. 	for i := 0; i < quantity; i++ {
  13. 		user := make([]rune, userLength)
  14. 		for i := range user {
  15. 			user[i] = letterRunes[seeded.Intn(len(letterRunes))]
  16. 		}
  17. 		emails = append(emails, fmt.Sprintf("%s@%s", string(user), domain))
  18. 	}
  20. 	b.Run("strings.Split", func(b *testing.B) {
  21. 		b.ReportAllocs()
  22. 		b.ResetTimer()
  23. 		var domain, tld string
  24. 		for i := 0; i < b.N; i++ {
  25. 			for _, email := range emails {
  26. 				domain, tld = stringsSplit(email)
  27. 			}
  28. 		}
  29. 		_, _ = domain, tld
  30. 	})
  31. 	b.Run("strings.SplitN", func(b *testing.B) {
  32. 		b.ReportAllocs()
  33. 		b.ResetTimer()
  34. 		var domain, tld string
  35. 		for i := 0; i < b.N; i++ {
  36. 			for _, email := range emails {
  37. 				domain, tld = stringsSplitN(email)
  38. 			}
  39. 		}
  40. 		_, _ = domain, tld
  41. 	})
  42. 	b.Run("strings.Index+strings.Split", func(b *testing.B) {
  43. 		b.ReportAllocs()
  44. 		b.ResetTimer()
  45. 		var domain, tld string
  46. 		for i := 0; i < b.N; i++ {
  47. 			for _, email := range emails {
  48. 				domain, tld = stringsIndexAndStringsSplit(email)
  49. 			}
  50. 		}
  51. 		_, _ = domain, tld
  52. 	})
  53. 	b.Run("regexp.Split", func(b *testing.B) {
  54. 		b.ReportAllocs()
  55. 		b.ResetTimer()
  56. 		var domain, tld string
  57. 		for i := 0; i < b.N; i++ {
  58. 			for _, email := range emails {
  59. 				domain, tld = regexpSplit(email)
  60. 			}
  61. 		}
  62. 		_, _ = domain, tld
  63. 	})
  64. 	b.Run("strings.Cut", func(b *testing.B) {
  65. 		b.ReportAllocs()
  66. 		b.ResetTimer()
  67. 		var domain, tld string
  68. 		for i := 0; i < b.N; i++ {
  69. 			for _, email := range emails {
  70. 				domain, tld = stringsCut(email)
  71. 			}
  72. 		}
  73. 		_, _ = domain, tld
  74. 	})
  1. cpu: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
  2. Benchmark
  3. Benchmark/strings.Split
  4. Benchmark/strings.Split-12         	        752	   1563851 ns/op	  640002 B/op	   20000 allocs/op
  5. Benchmark/strings.SplitN
  6. Benchmark/strings.SplitN-12        	        805	   1463329 ns/op	  640003 B/op	   20000 allocs/op
  7. Benchmark/strings.Index+strings.Split
  8. Benchmark/strings.Index+strings.Split-12   1416	    858783 ns/op	  320000 B/op	   10000 allocs/op
  9. Benchmark/regexp.Split
  10. Benchmark/regexp.Split-12                    85	  14605240 ns/op	11088513 B/op	  160024 allocs/op
  11. Benchmark/strings.Cut
  12. Benchmark/strings.Cut-12                   6597	    180579 ns/op	       0 B/op	       0 allocs/op
  13. PASS
英文:

Use strings.Split function

  1. 	email := &quot;learning@gmail.com&quot;
  2. split := strings.Split(email, &quot;@&quot;)
  3. split = strings.Split(split[1], &quot;.&quot;)
  4. fmt.Println(&quot;Domain:&quot;, split[0])
  5. fmt.Println(&quot;TLD:&quot;, split[1])

optionally you can validate an email string with mail.ParseAddress function

  1. 	email := &quot;learning@gmail.com&quot;
  2. addr, err := mail.ParseAddress(email)
  3. if err != nil {
  4. log.Fatal(err)
  5. }

> what if the TLD goes like this co.id, does the output still co.id ? –
@zacharyy

simply try to find the first index of . (strings.Index) and use one to separate the string

  1. 	email := &quot;learning@gmail.co.id&quot;
  2. split := strings.Split(email, &quot;@&quot;)
  3. index := strings.Index(split[1], &quot;.&quot;)
  4. fmt.Println(&quot;Domain:&quot;, split[1][:index])
  5. fmt.Println(&quot;TLD:&quot;, split[1][index+1:])

or use regexp.Split function

  1. 	email := &quot;learning@gmail.co.id&quot;
  2. split := strings.Split(email, &quot;@&quot;)
  3. split = regexp.MustCompile(&quot;[.]&quot;).
  4. Split(split[1], 2)
  5. fmt.Println(&quot;Domain:&quot;, split[0])
  6. fmt.Println(&quot;TLD:&quot;, split[1])

or strings.SplitN

  1.     email := &quot;learning@gmail.co.id&quot;
  2. split := strings.Split(email, &quot;@&quot;)
  3. split = strings.SplitN(split[1], &quot;.&quot;, 2)
  4. fmt.Println(&quot;Domain:&quot;, split[0])
  5. fmt.Println(&quot;TLD:&quot;, split[1])

or strings.Cut

  1. 	_, host, found := strings.Cut(email, &quot;@&quot;)
  2. if !found {
  3. t.Fatal(&quot;fail cut to host (Domain + TLD)&quot;)
  4. }
  5. domain, tld, found := strings.Cut(host, &quot;.&quot;)
  6. if !found {
  7. t.Fatal(&quot;fail cut to Domain and TLD&quot;)
  8. }
  9. fmt.Println(&quot;Domain:&quot;, domain)
  10. fmt.Println(&quot;TLD:&quot;, tld)

👉🏻 <kbd>PLAYGROUND</kbd> 👈🏻

Benchmarks

  1. 	const (
  2. quantity   = 10000
  3. userLength = 10
  4. domain     = &quot;gmail.com&quot;
  5. )
  6. var (
  7. letterRunes = []rune(&quot;abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ&quot;)
  8. emails      = make([]string, 0, quantity)
  9. seeded      = rand.New(rand.NewSource(time.Now().UnixMilli()))
  10. )
  11. for i := 0; i &lt; quantity; i++ {
  12. user := make([]rune, userLength)
  13. for i := range user {
  14. user[i] = letterRunes[seeded.Intn(len(letterRunes))]
  15. }
  16. emails = append(emails, fmt.Sprintf(&quot;%s@%s&quot;, string(user), domain))
  17. }
  18. b.Run(&quot;strings.Split&quot;, func(b *testing.B) {
  19. b.ReportAllocs()
  20. b.ResetTimer()
  21. var domain, tld string
  22. for i := 0; i &lt; b.N; i++ {
  23. for _, email := range emails {
  24. domain, tld = stringsSplit(email)
  25. }
  26. }
  27. _, _ = domain, tld
  28. })
  29. b.Run(&quot;strings.SplitN&quot;, func(b *testing.B) {
  30. b.ReportAllocs()
  31. b.ResetTimer()
  32. var domain, tld string
  33. for i := 0; i &lt; b.N; i++ {
  34. for _, email := range emails {
  35. domain, tld = stringsSplitN(email)
  36. }
  37. }
  38. _, _ = domain, tld
  39. })
  40. b.Run(&quot;strings.Index+strings.Split&quot;, func(b *testing.B) {
  41. b.ReportAllocs()
  42. b.ResetTimer()
  43. var domain, tld string
  44. for i := 0; i &lt; b.N; i++ {
  45. for _, email := range emails {
  46. domain, tld = stringsIndexAndStringsSplit(email)
  47. }
  48. }
  49. _, _ = domain, tld
  50. })
  51. b.Run(&quot;regexp.Split&quot;, func(b *testing.B) {
  52. b.ReportAllocs()
  53. b.ResetTimer()
  54. var domain, tld string
  55. for i := 0; i &lt; b.N; i++ {
  56. for _, email := range emails {
  57. domain, tld = regexpSplit(email)
  58. }
  59. }
  60. _, _ = domain, tld
  61. })
  62. b.Run(&quot;strings.Cut&quot;, func(b *testing.B) {
  63. b.ReportAllocs()
  64. b.ResetTimer()
  65. var domain, tld string
  66. for i := 0; i &lt; b.N; i++ {
  67. for _, email := range emails {
  68. domain, tld = stringsCut(email)
  69. }
  70. }
  71. _, _ = domain, tld
  72. })
  1. cpu: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
  2. Benchmark
  3. Benchmark/strings.Split
  4. Benchmark/strings.Split-12         	        752	   1563851 ns/op	  640002 B/op	   20000 allocs/op
  5. Benchmark/strings.SplitN
  6. Benchmark/strings.SplitN-12        	        805	   1463329 ns/op	  640003 B/op	   20000 allocs/op
  7. Benchmark/strings.Index+strings.Split
  8. Benchmark/strings.Index+strings.Split-12   1416	    858783 ns/op	  320000 B/op	   10000 allocs/op
  9. Benchmark/regexp.Split
  10. Benchmark/regexp.Split-12                    85	  14605240 ns/op	11088513 B/op	  160024 allocs/op
  11. Benchmark/strings.Cut
  12. Benchmark/strings.Cut-12                   6597	    180579 ns/op	       0 B/op	       0 allocs/op
  13. PASS

huangapple
  • 本文由 发表于 2022年11月1日 19:06:10
  • 转载请务必保留本文链接：https://go.coder-hub.com/74274942.html
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