RegEx re Replace

[McKirahan]

Can someone help me out?

I'm looking for a regular expression that inserts a space
into a string after every fourth byte (except the last).

Specifically, this is to display credit card numbers.


alert(doit("4444555566667777"));

// should return "4444 5555 6666 7777"

function doit(ccno) {
if (ccno.length % 4 != 0) return;
var what = ??????
return what;
}

Here's a non-regular expression approach:

var what = "";
for (var i=1; i<ccno.length/4+1; i++) {
if (what != "") what += " ";
what += ccno.substring(i*4-4,i*4);
}

Thanks in advance.

 

[Ivo]

I'm looking for a regular expression that inserts a space
into a string after every fourth byte (except the last).

Specifically, this is to display credit card numbers.

'1111222233334444'.replace( /(\w{4})/g, '$1 ' ).replace(/ +$/,'');

The first replacement puts the spaces in, the second one removes the
trailing space(s).
hth

 

[RobB]

Can someone help me out?

I'm looking for a regular expression that inserts a space
into a string after every fourth byte (except the last).

Specifically, this is to display credit card numbers.


alert(doit("4444555566667777"));

// should return "4444 5555 6666 7777"

function doit(ccno) {
if (ccno.length % 4 != 0) return;
var what = ??????
return what;
}

Here's a non-regular expression approach:

var what = "";
for (var i=1; i<ccno.length/4+1; i++) {
if (what != "") what += " ";
what += ccno.substring(i*4-4,i*4);
}

Thanks in advance.

x = x.replace(/(\d{3}\d\B)/g, '$1 ');

 

[McKirahan]

Can someone help me out?

I'm looking for a regular expression that inserts a space
into a string after every fourth byte (except the last).

[snip]

x = x.replace(/(\d{3}\d\B)/g, '$1 ');

Excellent!

Any recommendations on learning RegEx?

I have O'Reilly's "Mastering Regular Expressions"
but I haven't spent the time with it yet.

 

[RobB]

Can someone help me out?

I'm looking for a regular expression that inserts a space
into a string after every fourth byte (except the last).

[snip]

x = x.replace(/(\d{3}\d\B)/g, '$1 ');

Excellent!

Any recommendations on learning RegEx?

I have O'Reilly's "Mastering Regular Expressions"
but I haven't spent the time with it yet.

That O'Reilly book is phenomenal (although notably missing *any*
JavaScript implementations). I blow at regexes - but, for what it's
worth, try these...

http://www.webreference.com/js/column5/
http://www.regular-expressions.com/
http://www.devarticles.com/c/a/JavaScript/Regular-expressions-in-JavaScript/
http://d0om.fnal.gov/d0admin/doctaur/dtdocs/p-langs/web_prog_bookshelf/jscript/ch10_01.htm
http://www.evolt.org/article/Regular_Expressions_in_JavaScript/17/36435/

Any recommendations on learning RegEx?

Get a big bottle of Advil first. #:=o

 

[Dr John Stockton]

JRS: In article <[email protected]>, dated Thu, 31 Mar
2005 11:26:13, seen in McKirahan

Can someone help me out?

I'm looking for a regular expression that inserts a space
into a string after every fourth byte (except the last).

Specifically, this is to display credit card numbers.

Look for code that inserts thousands separators, change comma to space
and 3 to 4 - js-maths.htm .

That's if
T = S.replace(/^(\d{4})(\d{4})(\d{4})(\d{4})$/, "$1 $2 $3 $4")
does not please you.

CC numbers all have 16 digits, do they not?

 

[Csaba Gabor]

....
Any recommendations on learning RegEx?

....

I learned from
http://php.net/manual/en/reference.pcre.pattern.syntax.php
Dense, with many goodies javascript doesn't have,
but with many good examples, too, especially in the second half.

Csaba Gabor from Vienna

 

[McKirahan]

[snip]

CC numbers all have 16 digits, do they not?

4 ©


I think American Express and Diners Club are 15 digits.

http://money.howstuffworks.com/credit-card2.htm
http://javascript.internet.com/forms/val-credit-card.html