PHP e-mail address regular expression implementation and detailed, e-mail address regular expression _php tutorial

PHP e-mail address regular expression implementation and detailed, e-mail address regular expression

This article not only to tell about the regular Tatsu and also about the composition of the mailbox is the use of a detailed explanation, there is a need to understand the friend can refer to, at the same time we also provide a variety of different mailbox verification examples.
Regular expression.

^[_.0-9a-z-]+@ ([0-9a-z][0-9a-z-]+.) +[a-z]{2,3}$

In this regular expression, "+" means that the preceding string has one or more occurrences; "^" means that the next string must appear at the beginning and "$" means that the previous string must appear at the end;
“.” That is, ".", where "" is the escape character; "{2,3}" means that the preceding string can appear consecutively 2-3 times. "()" means that the contained content must appear in the target object at the same time. "[_.0-9a-z-]" means any character contained in "_", ".", "-", letters from A to Z range, and numbers in the range from 0 to 9;
In this way, the regular expression can be translated like this:
"The following character must be at the beginning (^)", "the character must be contained in" _ ",". ","-", letters from A to Z range, numbers in the range from 0 to 9 ([_.0-9a-z-])," precedes this character at least once (+) ", @," The string starts with a character that is contained in a number from A to Z range, from 0 to 9, followed by at least one of the characters contained in "-", any letter from A to Z range, from 0 to 9 in any number, and finally ends with. ([0-9a-z][0-9a-z- ]+.) "," Before this character appears at least once (+) "," the letter from the A to the Z range appears 2-3 times and ends with it ([a-z]{2,3}$) "

Code to copy code as follows
function Is_valid_email ($email, $test _mx = False)
{
if (eregi ("^ ([_a-z0-9-]+) (. [ _a-z0-9-]+) *@ ([a-z0-9-]+) (. [ a-z0-9-]+) * (. [ a-z]{2,4}) [Wind_phpcode_0]quot;, $email))
if ($test _mx)
{
List ($username, $domain) = Split ("@", $email);
Return Getmxrr ($domain, $mxrecords);
}
Else
return true;
Else
return false;
}

A domain name is made up of any combination of specific character sets, English letters, numbers, and "-" (that is, hyphens or minus signs) of each country's characters, but neither the beginning nor the end can contain "-", "-" cannot appear continuously. The letters in the domain name are not case-sensitive. The domain name can be up to 60 bytes long (including suffix. com,. NET,. org, and so on).
/^[a-z] ([a-z0-9]*[-_]?[ a-z0-9]+) *@ ([a-z0-9]*[-_]?[ a-z0-9]+) +[.] [A-z] {2,3} ([.] [A-z] {2})? $/i;
/content/I forms a case-insensitive regular expression;
^ Match start

$ match End

[A-z] e-mail prefix must be an English letter beginning

([A-z0-9]*[-_]? [a-z0-9]+] * and _a_2, AAA11, _1_a_2 match, and A1_, Aaff_33a_, A__aa do not match, if it is a null character, is also matched, * represents 0 or more.

* Represents 0 or more of the preceding characters.

[a-z0-9]* matches 0 or more English letters or numbers

[-_]? Match 0 or 1 "-" because "-" cannot appear continuously

[a-z0-9]+ matches 1 or more English letters or numbers, because "-" cannot be the end

@ must have a @

([A-z0-9]*[-_]? [a-z0-9]+] + see above ([a-z0-9]*[-_]?[ a-z0-9]+) * explanation, but cannot be empty, + denotes one or more.

[.] The special character (.) As ordinary characters

[A-z] {2,3} matches 2 to 3 English letters, typically COM or net.

([.] [A-z] {2})? Match 0 or 1 [.] [A-z] {2} (e.g.. CN, etc.) I don't know the general. Com.cn the last part is not all two-bit, if not please modify {2} to {start Word, end Word}

Perfect e-mail regular expression, with detailed explanation, please help test it! 2. Extract the email from the string:

Code to copy code as follows
function Getemail ($STR) {
$pattern = "/([A-z0-9]*[-_.]? [a-z0-9]+] *@ ([a-z0-9]*[-_]?[ a-z0-9]+) +[.] [A-z] {2,3} ([.] [A-z] {2})? /I ";
Preg_match_all ($pattern, $str, $EMAILARR);
return $EMAILARR [0];
}
$emailstr = "9999@qq.com.cn I am not a http://www.hzhuti.com/nokia/5235/vi place to open the IID mailing list: fuyongjie@163.com and hh@qq.com;. ;;, fuyongjie.100@yahoo.com,fu-1999@sina.com ";
$EMAILARR = Getemail ($EMAILSTR);
echo "

";
Print_r ($EMAILARR);
echo "

";
?> print as follows:
Array
(
[0] =>9999@qq.com.cn
[1] =>fuyongjie@163.com
[2] =>hh@qq.com
[3] =>fuyongjie.100@yahoo.com
[4] =>fu-1999@sina.com
) 3. Comparison: The 2nd in the regular is not the 1th ^ and $;

See the example again

Code to copy code as follows
function Funcemail ($STR)//mailbox Regular expression
{
Return (Preg_match ('/^[_.0-9a-z-a-z-]+@ ([0-9a-z][0-9a-z-]+.) +[a-z]{2,4}$/', $str))? True:false;
}//Verification Method One

$str = "qbcd@126.com.cn";
Preg_match ("/^[0-9a-z]+@ ([0-9a-z]+) [.]) +[a-z]{2,3}$/", $str, $re);
Print_r ($re);//e-mail authentication two

if (eregi ("^[_.0-9a-z-]+@" ([0-9a-z][0-9a-z-]+.) +[a-z]{2,3}$ ", $email)) {
echo "Your e-mail through a preliminary check";
}//third type of mailbox authentication method

if (Ereg ("/^[a-z") ([A-z0-9]*[-_.]? [a-z0-9]+] *@ ([a-z0-9]*[-_]?[ a-z0-9]+) +[.] [A-z] {2,3} ([.] [A-z] {2})? $/i; ", $email)) {
echo "Your email address is correct!";}
else{
echo "Please try again!";
}

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