10 Applicable PHP Regular expressions

10 Useful PHP Regular expressions

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.

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$email = "[email protected]"; if (preg_match('/^[^0-9][a-zA-Z0-9_]+([.][a-zA-Z0-9_]+)*[@][a-zA-Z0-9_]+([.][a-zA-Z0-9_]+)*[.][a-zA-Z]{2,4}$/',$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.

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if(filter_var([email protected]', 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.

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$username= "user_name12"; if(preg_match('/^[a-z\d_]{5,20}$/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.

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$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.

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$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.

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$zipcode = "12345-5434"; if (preg_match("/^([0-9]{5})(-[0-9]{4})?$/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.

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$SSN = " 333-23-2329 " ; if (Preg_match ( '/^[\d]{3}-[\d]{2}-[\d]{4}$/' $SSN Code class= "PHP plain") { echo Code class= "PHP string" > "Your SSN is ok." } else { echo "wrong SSN" }

7. Verify the credit card number

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

8. Verify the domain name

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$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

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$url = " Http://ansoncheung.tk/articles " ; preg_match ( ' @^ ( ?: HTTP//)? ([^/]+) @i ' $url $matches $host = Code class= "PHP variable" > $matches [1]; echo $host ;

10. Highlight the keywords in the text

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$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", '\1', $text); echo$text;

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