10 practical PHP regular expressions, practical PHP regular expressions

10 practical PHP regular expressions, practical PHP regular expressions_PHP tutorial

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Release： 2016-07-13 10:00:58

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10 Practical PHP Regular Expressions, Practical PHP Regular Expressions

Regular expressions are an important element in program development. They provide methods for describing or matching text. Strings, such as specific characters, words or calculations, etc. But in some cases, using regular expressions to validate a string is complex and time-consuming. This article introduces you to 10 common and practical ways of writing PHP regular expressions. I hope it will be helpful to your work.

　1. Verify email address

This is a regular expression used to validate emails. But it's not an efficient, perfect solution. Not recommended here.

1 2 3 4 5 6 $email = "test@ansoncheung.tk"; if (preg_match('/^[^0-9][a-zA-Z0-9_] ([.][a-zA-Z0-9_] )*[@][a-zA-Z0-9_] ([.][a-zA-Z0-9_] )*[.][a-zA-Z]{2,4}$/',$email)) { echo "Your email is ok."; } else { echo "Wrong email address format"; }

In order to verify email addresses more effectively, it is recommended to use filer_var.

1 2 3 4 5 if (filter_var('test email@ansoncheung', FILTER_VALIDATE_EMAIL)) { echo "Your email is ok."; } else { echo "Wrong email address format."; }

　2. Verify username

This is an example for validating a username, which includes 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, you can also make reasonable modifications to the minimum and maximum values as needed.

1 2 3 4 5 6 $username = "user_name12"; if (preg_match('/^[a-zd_]{5,20}$/i', $username)) { echo "Your username is ok."; } else { echo "Wrong username format."; }

　3. Verify phone number

This is an example of verifying a US phone number.

1 2 3 4 5 6 $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 IP address

This is an example used to verify IPv4 addresses.

1 2 3 4 5 6 $IP = "198.168.1.78"; if (preg_match('/^(([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]).){3}([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/',$IP)) { echo "Your IP address is ok."; } else { echo "Wrong IP address."; }

　5. Verify postal code

This is an example for validating postal codes.

1 2 3 4 5 6 $zipcode = "12345-5434"; if (preg_match("/^([0-9]{5})(-[0-9]{4})?$/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 the US SSN.

1 2 3 4 5 6 $ssn = "333-23-2329"; if (preg_match('/^[d]{3}-[d]{2}-[d]{4}$/',$ssn)) { echo "Your SSN is ok."; } else { echo "Wrong SSN."; }

　7. Verify credit card number

1 2 3 4 5 6 $cc = "378282246310005"; if (preg_match('/^(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|6011[0-9]{12}|3(?:0[0-5]|[68][0-9])[0-9]{11}|3[47][0-9]{13})$/', $cc)) { echo "Your credit card number is ok."; } else { echo "Wrong credit card number."; }

8. Verify domain name

1 2 3 4 5 6 $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. Extract domain name from specific URL

1 2 3 4 $url = "http://ansoncheung.tk/articles"; preg_match('@^(?:http://)?([^/] )@i', $url, $matches); $host = $matches[1]; echo $host;

10. Highlight the keywords in the text

1 2 3 $text = "Sample sentence from AnsonCheung.tk, regular expression has 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 regexen) are written in a formal language that can be interpreted by a regular expression processor"; $text = preg_replace("/b(regex)b/i", '<span>, $text); echo $text;