Solved

preg_match in PHP

Posted on 2014-11-20
6
127 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
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 34

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
Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

 
LVL 11

Expert Comment

by:Radek Baranowski
ID: 40456901
yes.
0
 
LVL 108

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

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

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…
Things That Drive Us Nuts Have you noticed the use of the reCaptcha feature at EE and other web sites?  It wants you to read and retype something that looks like this.Insanity!  It's not EE's fault - that's just the way reCaptcha works.  But it is …
The viewer will learn how to count occurrences of each item in an array.
The viewer will learn how to create a basic form using some HTML5 and PHP for later processing. Set up your basic HTML file. Open your form tag and set the method and action attributes.: (CODE) Set up your first few inputs one for the name and …

863 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

Need Help in Real-Time?

Connect with top rated Experts

26 Experts available now in Live!

Get 1:1 Help Now