10 useful php Regular expression summaries, PHP regular expression Rollup _php tutorial

10 Useful PHP Regular Expressions Summary, PHP Regular Expression summary

In this paper, 10 practical PHP regular expressions are summarized and shared for everyone's reference. Specific as follows:

A regular expression is an important element in the development of a program that provides a string that describes or matches text, such as a specific character, word, or calculation. But in some cases, using regular expressions to verify that a string is more complex and time-consuming. This article gives you a description of 10 common PHP regular expressions that I hope will help you with your work.

1. Verify the e-mail address

This is a regular expression for validating e-mail messages. But it's not an efficient, perfect solution. Not recommended for use here.

Copy the Code code as follows: $email = "test@ansoncheung.tk";
if (Preg_match ('/^[^0-9][a-za-z0-9_]+ ([.] [a-za-z0-9_]+) *[@][a-za-z0-9_]+ ([.] [a-za-z0-9_]+) *[.] [A-za-z] {2,4}$/', $email)) {
echo "Your email is ok.";
} else {
echo "Wrong email address format";
}
For more effective verification of e-mail addresses, we recommend using Filer_var.

Copy the Code code as follows: if (Filter_var (' Test+email@ansoncheung ', Filter_validate_email)) {
echo "Your email is ok.";
} else {
echo "wrong email address format.";
}

2. Verify the user name

This is an instance that validates the user name, including letters, numbers (a-z,a-z,0-9), underscores, and a minimum of 5 characters, and a maximum of 20 characters. At the same time, the minimum and maximum values can be modified as needed.

Copy the Code code as follows: $username = "User_name12";
if (Preg_match ('/^[a-z\d_]{5,20}$/i ', $username)) {
echo "Your username is ok.";
} else {
echo "wrong username format.";
}

3. Verify the phone number

This is an example of verifying a U.S. phone number.

Copy the Code code as follows: $phone = "(021) 423-2323";
if (Preg_match ('/\ (? \d{3}\)? [ -\s.]? \d{3}[-\s.] \d{4}/x ', $phone)) {
echo "Your phone number is ok.";
} else {
echo "wrong phone number.";
}

4. Verify the IP address

This is an instance to validate the IPV4 address.

Copy the Code code as follows: $IP = "198.168.1.78";
if (Preg_match ('/^ ([1-9]?[ 0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]).) {3} ([1-9]? [0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]) $/', $IP)) {
echo "Your IP address is ok.";
} else {
echo "Wrong IP address.";
}

5. Verify the ZIP code

This is an instance to validate the ZIP code.

Copy the Code code as follows: $zipcode = "12345-5434";
if (Preg_match ("/^ ([0-9]{5}) (-[0-9]{4})? $/i", $zipcode)) {
echo "Your Zip code is OK.";
} else {
echo "Wrong Zip code.";
}

6. Verify SSN (Social Security Number)

This is an example of verifying a US ssn.

Copy the Code code as follows: $SSN = "333-23-2329";
if (Preg_match ('/^[\d]{3}-[\d]{2}-[\d]{4}$/', $ssn)) {
echo "Your SSN is ok.";
} else {
echo "wrong SSN.";
}

7. Verify the credit card number

Copy the Code code as follows: $CC = "378282246310005";
if (Preg_match (?: 4[0-9]{12} (?: [0-9]{3})? | 5[1-5][0-9]{14}|6011[0-9]{12}|3 (?: 0 [0-5]| [68] [0-9]) [0-9] {11}|3[47][0-9]{13}) $/', $cc)) {
echo "Your credit card number is OK.";
} else {
echo "Wrong credit card number.";
}

8. Verify the domain name

Copy the Code code as follows: $url = "http://ansoncheung.tk/";
if (Preg_match ('/^ (http|https|ftp): \/\/([a-z0-9][a-z0-9_-]*] (?: \. [A-z0-9] [a-z0-9_-]*) +):? (\d+) \/?/i ', $url)) {
echo "Your URL is ok.";
} else {
echo "wrong URL.";
}

9. Extracting a domain name from a specific URL

Copy the Code code as follows: $url = "Http://ansoncheung.tk/articles";
Preg_match (' @^ (?:/HTTP//)? ( [^/]+) @i ', $url, $matches);
$host = $matches [1];
Echo $host;

10. Highlight the keywords in the text

Copy the code as follows: $text = "Sample sentence from ansoncheung.tk, regular expression had become popular in web programming. Now we learn regex. According to Wikipedia, Regular expressions (abbreviated as Regex or regexp, with plural forms regexes, regexps, or Regexe N) is written in a formal language that can is interpreted by a regular expression processor ";
$text = Preg_replace ("/\b (regex) \b/i", '\1', $text);
Echo $text;

I hope this article is helpful to everyone's PHP programming.

How PHP uses regular expressions to extract a contiguous 10-digit number from a piece of content

[^\d] (? \d{10}) ([^\d]|$)

How does PHP use variables in a regular expression?

int Preg_match (string $pattern, String $subject [, array $matches [, int $flags]])
String $pattern is a string, so it is possible to first calculate this string into a variable
$star = ' a ';
$stop = ' C ';
$info = ' a1b2c3 ';
$pattern = '/'. $star. ' (.+?)'. $stop. ' /';
Preg_match ($pattern, $info, $result);
Print_r ($result [1]);

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