查找、解析和验证电子邮件地址

Question

import "fmt"
func main() {
email := "[e-mail]"
atTrue := false
s := ""
for i := 0; i < len(email); i++ {
if atTrue {
s += string(email[i])
}
if string(email[i]) == "@" {
atTrue = true
}
}
fmt.Println(s)
}

电流输出：gmail.com

预期输出：域：gmail和TLD:com

如何指示从某个字符串到某个字符串的循环？

Answer 1

使用字符串。拆分功能

email := "[e-mail]"
split := strings.Split(email, "@")
split = strings.Split(split[1], ".")
fmt.Println("Domain:", split[0])
fmt.Println("TLD:", split[1])

您可以选择使用邮件验证电子邮件字符串。ParseAddress函数

email := "[e-mail]"
addr, err := mail.ParseAddress(email)
if err != nil {
log.Fatal(err)
}

如果TLD像这样co.id，输出仍然是co.id吗？-@zacharyy

只需尝试查找.(strings.Index)的第一个index，并使用一个来分离字符串

email := "[e-mail]"
split := strings.Split(email, "@")
index := strings.Index(split[1], ".")
fmt.Println("Domain:", split[1][:index])
fmt.Println("TLD:", split[1][index+1:])

或者使用regexp。拆分功能

email := "[e-mail]"
split := strings.Split(email, "@")
split = regexp.MustCompile("[.]").
Split(split[1], 2)
fmt.Println("Domain:", split[0])
fmt.Println("TLD:", split[1])

或字符串。SplitN

email := "[e-mail]"
split := strings.Split(email, "@")
split = strings.SplitN(split[1], ".", 2)
fmt.Println("Domain:", split[0])
fmt.Println("TLD:", split[1])

或字符串。剪切

_, host, found := strings.Cut(email, "@")
if !found {
t.Fatal("fail cut to host (Domain + TLD)")
}
domain, tld, found := strings.Cut(host, ".")
if !found {
t.Fatal("fail cut to Domain and TLD")
}
fmt.Println("Domain:", domain)
fmt.Println("TLD:", tld)

游乐场

基准

const (
quantity   = 10000
userLength = 10
domain     = "gmail.com"
)
var (
letterRunes = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
emails      = make([]string, 0, quantity)
seeded      = rand.New(rand.NewSource(time.Now().UnixMilli()))
)
for i := 0; i < quantity; i++ {
user := make([]rune, userLength)
for i := range user {
user[i] = letterRunes[seeded.Intn(len(letterRunes))]
}
emails = append(emails, fmt.Sprintf("%s@%s", string(user), domain))
}
b.Run("strings.Split", func(b *testing.B) {
b.ReportAllocs()
b.ResetTimer()
var domain, tld string
for i := 0; i < b.N; i++ {
for _, email := range emails {
domain, tld = stringsSplit(email)
}
}
_, _ = domain, tld
})
b.Run("strings.SplitN", func(b *testing.B) {
b.ReportAllocs()
b.ResetTimer()
var domain, tld string
for i := 0; i < b.N; i++ {
for _, email := range emails {
domain, tld = stringsSplitN(email)
}
}
_, _ = domain, tld
})
b.Run("strings.Index+strings.Split", func(b *testing.B) {
b.ReportAllocs()
b.ResetTimer()
var domain, tld string
for i := 0; i < b.N; i++ {
for _, email := range emails {
domain, tld = stringsIndexAndStringsSplit(email)
}
}
_, _ = domain, tld
})
b.Run("regexp.Split", func(b *testing.B) {
b.ReportAllocs()
b.ResetTimer()
var domain, tld string
for i := 0; i < b.N; i++ {
for _, email := range emails {
domain, tld = regexpSplit(email)
}
}
_, _ = domain, tld
})
b.Run("strings.Cut", func(b *testing.B) {
b.ReportAllocs()
b.ResetTimer()
var domain, tld string
for i := 0; i < b.N; i++ {
for _, email := range emails {
domain, tld = stringsCut(email)
}
}
_, _ = domain, tld
})

cpu: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
Benchmark
Benchmark/strings.Split
Benchmark/strings.Split-12                  752    1563851 ns/op      640002 B/op      20000 allocs/op
Benchmark/strings.SplitN
Benchmark/strings.SplitN-12                 805    1463329 ns/op      640003 B/op      20000 allocs/op
Benchmark/strings.Index+strings.Split
Benchmark/strings.Index+strings.Split-12   1416     858783 ns/op      320000 B/op      10000 allocs/op
Benchmark/regexp.Split
Benchmark/regexp.Split-12                    85   14605240 ns/op    11088513 B/op     160024 allocs/op
Benchmark/strings.Cut
Benchmark/strings.Cut-12                   6597     180579 ns/op           0 B/op          0 allocs/op
PASS