使用PHP中的正则表达式验证电子邮件
我在正则表达式方面非常新颖。 我正在开发一个PHP项目，我需要验证电子邮件地址。 在这个网站和谷歌搜索后，我发现下面的正则表达式说它应该最好。
if (preg_match("/^(?!(?:(?:x22?x5C[x00-x7E]x22?)|(?:x22?[^x5Cx22]x22?)){255,})(?!(?:(?:x22?x5C[x00-x7E]x22?)|(?:x22?[^x5Cx22]x22?)){65,}@)(?:(?:[x21x23-x27x2Ax2Bx2Dx2F-x39x3Dx3Fx5E-x7E]+)|(?:x22(?:[x01-x08x0Bx0Cx0E-x1Fx21x23-x5Bx5D-x7F]|(?:x5C[x00-x7F]))*x22))(?:.(?:(?:[x21x23-x27x2Ax2Bx2Dx2F-x39x3Dx3Fx5E-x7E]+)|(?:x22(?:[x01-x08x0Bx0Cx0E-x1Fx21x23-x5Bx5D-x7F]|(?:x5C[x00-x7F]))*x22)))*@(?:(?:(?!.*[^.]{64,})(?:(?:(?:xn--)?[a-z0-9]+(?:-[a-z0-9]+)*.){1,126}){1,}(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-[a-z0-9]+)*)|(?:[(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|(?:(?!(?:.*[a-f0-9][:]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}:)|(?:(?!(?:.*[a-f0-9]:){5,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}:)?)))?(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:.(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))]))$/iD", strtolower($mail_address))) {
echo "valid email";
}
但是当我使用它时，我得到错误说，
"Warning: preg_match(): No ending delimiter '/' found"
这段代码有什么问题？
使用它而不是正则表达式：
if(filter_var($email, FILTER_VALIDATE_EMAIL)) {
//Valid email!
}
不推荐使用正则表达式来验证电子邮件地址，因为它肯定不是很好，特别是如果您不想排除某些具有根据RFC 822语法正确的有效电子邮件地址的人。
http://www.php.net/filter_var是你最好的选择。
根据RFC 822语法尝试验证电子邮件地址的正则表达式的一个疯狂示例：
(?:(?:rn)?[ t])*(?:(?:(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t]
)+|Z|(?=[["()<>@,;:".[]]))|"(?:[^"r]|.|(?:(?:rn)?[ t]))*"(?:(?:
rn)?[ t])*)(?:.(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(
?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|"(?:[^"r]|.|(?:(?:rn)?[
t]))*"(?:(?:rn)?[ t])*))*@(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00-
31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*
](?:(?:rn)?[ t])*)(?:.(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+
(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*](?:
(?:rn)?[ t])*))*|(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z
|(?=[["()<>@,;:".[]]))|"(?:[^"r]|.|(?:(?:rn)?[ t]))*"(?:(?:rn)
?[ t])*)*<(?:(?:rn)?[ t])*(?:@(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:
rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*](?:(?:rn)?[
t])*)(?:.(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)
?[ t])+|Z|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t]
)*))*(?:,@(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[
t])+|Z|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*
)(?:.(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t]
)+|Z|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*))*)
*:(?:(?:rn)?[ t])*)?(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+
|Z|(?=[["()<>@,;:".[]]))|"(?:[^"r]|.|(?:(?:rn)?[ t]))*"(?:(?:r
n)?[ t])*)(?:.(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:
rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|"(?:[^"r]|.|(?:(?:rn)?[ t
]))*"(?:(?:rn)?[ t])*))*@(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31
]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*](
?:(?:rn)?[ t])*)(?:.(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?
:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*](?:(?
:rn)?[ t])*))*>(?:(?:rn)?[ t])*)|(?:[^()<>@,;:".[] 00- 31]+(?:(?
:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|"(?:[^"r]|.|(?:(?:rn)?
[ t]))*"(?:(?:rn)?[ t])*)*:(?:(?:rn)?[ t])*(?:(?:(?:[^()<>@,;:".[]
00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|"(?:[^"r]|
.|(?:(?:rn)?[ t]))*"(?:(?:rn)?[ t])*)(?:.(?:(?:rn)?[ t])*(?:[^()<>
@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|"
(?:[^"r]|.|(?:(?:rn)?[ t]))*"(?:(?:rn)?[ t])*))*@(?:(?:rn)?[ t]
)*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:
".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*)(?:.(?:(?:rn)?[ t])*(?
:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[
]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*))*|(?:[^()<>@,;:".[] 00-
31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|"(?:[^"r]|.|(
?:(?:rn)?[ t]))*"(?:(?:rn)?[ t])*)*<(?:(?:rn)?[ t])*(?:@(?:[^()<>@,;
:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|[([
^[]r]|.)*](?:(?:rn)?[ t])*)(?:.(?:(?:rn)?[ t])*(?:[^()<>@,;:"
.[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|[([^[
]r]|.)*](?:(?:rn)?[ t])*))*(?:,@(?:(?:rn)?[ t])*(?:[^()<>@,;:".
[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|[([^[]
r]|.)*](?:(?:rn)?[ t])*)(?:.(?:(?:rn)?[ t])*(?:[^()<>@,;:".[]
00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|[([^[]r]
|.)*](?:(?:rn)?[ t])*))*)*:(?:(?:rn)?[ t])*)?(?:[^()<>@,;:".[]
00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|"(?:[^"r]|
.|(?:(?:rn)?[ t]))*"(?:(?:rn)?[ t])*)(?:.(?:(?:rn)?[ t])*(?:[^()<>@,
;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]]))|"(?
:[^"r]|.|(?:(?:rn)?[ t]))*"(?:(?:rn)?[ t])*))*@(?:(?:rn)?[ t])*
(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".
[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*)(?:.(?:(?:rn)?[ t])*(?:[
^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[]
]))|[([^[]r]|.)*](?:(?:rn)?[ t])*))*>(?:(?:rn)?[ t])*)(?:,s*(
?:(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:
".[]]))|"(?:[^"r]|.|(?:(?:rn)?[ t]))*"(?:(?:rn)?[ t])*)(?:.(?:(
?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[
["()<>@,;:".[]]))|"(?:[^"r]|.|(?:(?:rn)?[ t]))*"(?:(?:rn)?[ t
])*))*@(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t
])+|Z|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*)(?
:.(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|
Z|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*))*|(?:
[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".[
]]))|"(?:[^"r]|.|(?:(?:rn)?[ t]))*"(?:(?:rn)?[ t])*)*<(?:(?:rn)
?[ t])*(?:@(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["
()<>@,;:".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*)(?:.(?:(?:rn)
?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>
@,;:".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*))*(?:,@(?:(?:rn)?[
t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,
;:".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*)(?:.(?:(?:rn)?[ t]
)*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:
".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*))*)*:(?:(?:rn)?[ t])*)?
(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[["()<>@,;:".
[]]))|"(?:[^"r]|.|(?:(?:rn)?[ t]))*"(?:(?:rn)?[ t])*)(?:.(?:(?:
rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z|(?=[[
"()<>@,;:".[]]))|"(?:[^"r]|.|(?:(?:rn)?[ t]))*"(?:(?:rn)?[ t])
*))*@(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])
+|Z|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*)(?:
.(?:(?:rn)?[ t])*(?:[^()<>@,;:".[] 00- 31]+(?:(?:(?:rn)?[ t])+|Z
|(?=[["()<>@,;:".[]]))|[([^[]r]|.)*](?:(?:rn)?[ t])*))*>(?:(
?:rn)?[ t])*))*)?;s*)
你应该使用函数filter_vars()来验证你的输入，而不是你自己的正则表达式。
例：
filter_var('bob@example.com', FILTER_VALIDATE_EMAIL)
文档中的更多信息：http：//php.net/manual/en/function.filter-var.php
看起来你并不需要更大的代码来验证电子邮件。
<?php
$email = "abc123@sdsd.com";
$regex = '/^[_a-z0-9-]+(.[_a-z0-9-]+)*@[a-z0-9-]+(.[a-z0-9-]+)*(.[a-z]{2,3})$/';
if (preg_match($regex, $email)) {
echo $email . " is a valid email. We can accept it.";
} else {
echo $email . " is an invalid email. Please try again.";
}
?>
试试这个，让我知道
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