Solved

preg_match in PHP

Posted on 2014-11-20
6
133 Views
Last Modified: 2014-11-23
Any idea what this preg_match want to do ? Tks

if(!preg_match(“/^[4]{1,1}[0-9]{12,15}$/”,$value))
0
Comment
Question by:AXISHK
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
6 Comments
 
LVL 11

Accepted Solution

by:
Radek Baranowski earned 200 total points
ID: 40456786
http://www.autohotkey.com/docs/misc/RegEx-QuickRef.htm

it matches a string that
begins (^) with exactly one ({1,1}) "4" then is followed by 12 to 15 digits 0-9

so, the pattern like:

41234567890123

hope this helps!
0
 
LVL 35

Assisted Solution

by:Dan Craciun
Dan Craciun earned 100 total points
ID: 40456816
I think the string was done so you can quickly change the amounts of digits at the beginning, or else {1,1} is meaningless.
As is, the pattern can be written as
^4\d{12,15}$

HTH,
Dan
0
 

Author Comment

by:AXISHK
ID: 40456898
^4\d{12,15}$

Does it mean starting with '4", following by 12 - 15 digit number ? Tks
0
PeopleSoft Has Never Been Easier

PeopleSoft Adoption Made Smooth & Simple!

On-The-Job Training Is made Intuitive & Easy With WalkMe's On-Screen Guidance Tool.  Claim Your Free WalkMe Account Now

 
LVL 11

Expert Comment

by:Radek Baranowski
ID: 40456901
yes.
0
 
LVL 110

Assisted Solution

by:Ray Paseur
Ray Paseur earned 200 total points
ID: 40457118
There is one other problem.  The apparent double quote wrapping the regular expression are not, in fact, quotes.  They may be something that wormed its way in from cut/paste with Microsoft word?  You may want to read this article about how PHP handles quote marks.  It's an important part of the language with many effects on the meaning of the code.
http://www.experts-exchange.com/Web_Development/Web_Languages-Standards/PHP/A_12241-Quotation-Marks-in-PHP.html

You may find that your regular expressions are easier to craft and understand if you write them like this, with comments to explain the intent of each segment of the expression:
$rgx 
= '#'           // REGEX DELIMITER (REQUIRED AT FRONT AND BACK OF EXPRESSION)
. '^'           // AT THE START OF THE STRING
. '[4]'         // CHARACTER CLASS THAT INCLUDES ONLY "4"
. '{1,1}'       // EXACTLY ONE OF THIS CHARACTER CLASS
. '[0-9]'       // CHARACTER CLASS THAT INCLUDES DIGITS 0-9
. '{12,15}'     // BETWEEN 12 AND 15 OF THE DIGITS
. '$'           // AT THE END OF THE STRING
. '#'           // REGEX DELIMITER
;

Open in new window

In the instant case this looks like  the regex is intended to match certain kinds of credit card numbers.
0
 

Author Closing Comment

by:AXISHK
ID: 40461371
Tks
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Foreword (July, 2015) Since I first wrote this article, years ago, a great many more people have begun using the internet.  They are coming online from every part of the globe, learning, reading, shopping and spending money at an ever-increasing ra…
Nothing in an HTTP request can be trusted, including HTTP headers and form data.  A form token is a tool that can be used to guard against request forgeries (CSRF).  This article shows an improved approach to form tokens, making it more difficult to…
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…
This tutorial will teach you the core code needed to finalize the addition of a watermark to your image. The viewer will use a small PHP class to learn and create a watermark.

734 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question