正则表达式验证邮箱并剔除前后空格

Question

[\s*\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*\s*]

Answer 1

用filter，不用想正则想到头大
另外去除前后空格可以用trim()Example #1 Validating email addresses with filter_var()<?php
$email_a = '[email protected]';
$email_b = 'bogus';if (filter_var($email_a, FILTER_VALIDATE_EMAIL)) {
    echo "This (email_a) email address is considered valid.";
}
if (filter_var($email_b, FILTER_VALIDATE_EMAIL)) {
    echo "This (email_b) email address is considered valid.";
}
?> Example #1 Sanitizing and validating email addresses<?php
$a = '[email protected]';
$b = 'bogus - at - example dot org';
$c = '([email protected])';$sanitized_a = filter_var($a, FILTER_SANITIZE_EMAIL);
if (filter_var($sanitized_a, FILTER_VALIDATE_EMAIL)) {
    echo "This (a) sanitized email address is considered valid.\n";
}$sanitized_b = filter_var($b, FILTER_SANITIZE_EMAIL);
if (filter_var($sanitized_b, FILTER_VALIDATE_EMAIL)) {
    echo "This sanitized email address is considered valid.";
} else {
    echo "This (b) sanitized email address is considered invalid.\n";
}$sanitized_c = filter_var($c, FILTER_SANITIZE_EMAIL);
if (filter_var($sanitized_c, FILTER_VALIDATE_EMAIL)) {
    echo "This (c) sanitized email address is considered valid.\n";
    echo "Before: $c\n";
    echo "After:  $sanitized_c\n";    
}
?> 
以上例程会输出：This (a) sanitized email address is considered valid.
This (b) sanitized email address is considered invalid.
This (c) sanitized email address is considered valid.
Before: ([email protected])
After: [email protected]

Answer 2

preg_match('/^[\w-]+(\.[\w-]+)*@[\w-]+(\.[\w-]+)+$/',trim($filename))

Answer 3

<?php
$email = "someone@exa mple.com";if(!filter_var($email, FILTER_VALIDATE_EMAIL))
 {
 echo "E-mail is not valid";
 }
else
 {
 echo "E-mail is valid";
 }
?>

Answer 4

你可以参考这里
http://www.w3school.com.cn/php/php_ref_filter.asp

Answer 5

我刚才才重新做了一个循环10000次的实验,发现下边的这个例子用时60毫秒,
IF(Preg_match("/^[[:alnum:]._-]+@[[:alnum:]-]+\.([[:alnum:]-]+\.)*[[:alnum:]]+$/isU",$??)){
Echo "Email地址合法.";
}而这下边的这个用时为200毫秒
IF(Filter_var($??,FILTER_VALIDATE_EMAIL)){
Echo "Email地址合法.";
}由此可见在判断email地址的合法性上,正则表达式的效率反而比Filter_var函数的效率要高很多,所以就看你要如何取舍了.