simple regular expression but not work

[den]

if I have:
string=/AAA/B/file.jpg;

if I want change first slash, I writeo:
var regexp = /\//;
var_2 = stringa.replace(regexp, "zzz");

ok work and I have:
zzzAAA/B/file.jpg;

but if I want change only the last slash; this code not work:
var regexp = /$\//;

where is my error?

[Bart Van der Donck]

den wrote:

if I have:
string=/AAA/B/file.jpg;

if I want change first slash, I writeo:
var regexp = /\//;
var_2 = stringa.replace(regexp, "zzz");

ok work and I have:
zzzAAA/B/file.jpg;

but if I want change only the last slash; this code not work:
var regexp = /$\//;

where is my error?

$ must come last and can't be followed by anything else. A simple way
to overcome your problem is to reverse the string, then execute your
initial regex and then reverse it back:

var string = '/AAA/B/file.jpg';
var r = '';
for (i = string.length - 1; i >= 0; i--)
r += string.charAt(i);
r = r.replace(/\//, 'zzz')
var string = '';
for (var j = r.length - 1; j >= 0; j--)
string += r.charAt(j);
alert(string);

Hope this helps,

--
Bart

[den]

Il 25 Feb 2007 01:32:38 -0800, Bart Van der Donck ha scritto:

den wrote:

>if I have:
string=/AAA/B/file.jpg;

if I want change first slash, I writeo:
var regexp = /\//;
var_2 = stringa.replace(regexp, "zzz");

ok work and I have:
zzzAAA/B/file.jpg;

but if I want change only the last slash; this code not work:
var regexp = /$\//;

where is my error?

if I use this :
/\/$/
why not work ?
I have insert the $ at the end

[Evertjan.]

den wrote on 25 feb 2007 in comp.lang.javascript:

Il 25 Feb 2007 01:32:38 -0800, Bart Van der Donck ha scritto:

>den wrote:

>>if I have:
string=/AAA/B/file.jpg;

use quotes for a litteral string!

do not use the reserved word "string" for a variable,
but stringa as you reference below!!!

>>>
if I want change first slash, I writeo:
var regexp = /\//;
var_2 = stringa.replace(regexp, "zzz");

ok work and I have:
zzzAAA/B/file.jpg;

but if I want change only the last slash; this code not work:
var regexp = /$\//;

where is my error?

if I use this :
/\/$/
why not work ?
I have insert the $ at the end

No, that should only work if the $ is te last char.

Try:

<script type='text/javascript'>

s ='/AAA/B/file.jpg';

var regexp = /\/([^\/]*)$/;
var2 = s.replace(regexp, "zzz$1");

alert(var2);

</script>

--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[g4toloc0]

:)

Evertjan has posted my same solution.. but i have added a little
explanation so there's my answer to the problem.

if I use this :
/\/$/
why not work ?
I have insert the $ at the end

As Bart is correctly saying '$' is not a 'last occurrence identifier'.
It is used to match the end of the line (while ^ is used to match the
beginning of the line).

/\/$/ -this regexp means:
match a / at the end of the line.

I think you need to read some docs about regular expressions..
Start with this one:
http://www.perl.com/doc/manual/html/pod/perlre.html
(javascript does not support all perl regexps modifiers but i think it
is a good point to start)

About your question.. you can use a single regexp (Bart solution is
actually working but regexps are so powerful)

Try this one:

var stringa='/AAA/B/file.jpg';
//same note about Evertjan about using string as a var name..
var var_2=stringa.replace(/\/([^\/]+$)/,'zzz$1');
alert(var_2);
alert(RegExp.$1); //the file name

My regexp can be translated to:

match a /
then match any character that is not a / and keep going since you
reach the end of the line.
Then, replace / with zzz and all chars we saved on the first group.

Ciao.
Seba

[den]

very thanks at all;

only a small question

in the last example
you use
alert(RegExp.$1);

but this parameter RegExp function in all modern browser?
in all version of javascript?

[den]

Il 25 Feb 2007 02:24:38 -0800, g4toloc0 ha scritto:

:)

Evertjan has posted my same solution.. but i have added a little
explanation so there's my answer to the problem.

>if I use this :
/\/$/
why not work ?
I have insert the $ at the end

As Bart is correctly saying '$' is not a 'last occurrence identifier'.
It is used to match the end of the line (while ^ is used to match the
beginning of the line).

/\/$/ -this regexp means:
match a / at the end of the line.

I think you need to read some docs about regular expressions..
Start with this one:

what is the difference between this (Evertjian)
/\/([^\/]*)$/
and your:
/\/([^\/]+$)/

your $ is inner () and have a + .

CAn you does examples of difference?


only a small question

in the last example
you use
alert(RegExp.$1);

but this parameter RegExp function in all modern browser?
in all version of javascript?

very thanks at all;

[g4toloc0]

what is the difference between this (Evertjian)

/\/([^\/]*)$/
and your:
/\/([^\/]+$)/

* Match 0 or more times
+ Match 1 or more times

that means that Evertjian code will match something like:
var stringa='/AAA/B/';
While my code will not.

My regexp says:
When you found a '/', search at least one character that is not '/'
before reaching the end of the line.

In other words Evertjian RE does not need a file name after the last
'/'

your $ is inner () and have a + .

CAn you does examples of difference?

Caret and dollar are a bit 'weird'... they match a position in the
line rather than a char.
So (at least for this example) ')$' is the same as '$)'... but
Evertjian ')$' is a little more 'syntactically correct'.
[you often need to deal with '$)' when building very complex
regepxs]

in the last example
you use
alert(RegExp.$1);
but this parameter RegExp function in all modern browser?
in all version of javascript?

you need at least javascript 1.2 (a.k.a JScript, ECMAScript or
ECMA-262)
It is supported by IE4+, NS4+, FF (all versions) and most other modern
browsers.

Mmmm... enough talking for now..

Ciao, ciao.
Seba.

[Dr J R Stockton]

In comp.lang.javascript message <yg****************************@40tude.n
et>, Sun, 25 Feb 2007 11:43:45, den <sp*****@not.notposted:

>very thanks at all;

only a small question

in the last example
you use
alert(RegExp.$1);

but this parameter RegExp function in all modern browser?
in all version of javascript?

Possibly; but the usage is not given in ISO/IEC 16262. It is deprecated
for javascript, and one should instead index the result of .exec or
..match. See in <URL:http://www.merlyn.demon.co.uk/js-valid.htm>.

I have heard that in JScript.NET with ASP.NET the RegExp.$1 notation is
not available.

Query : I want to find a way of detecting all and only instances of such
deprecated usage on my site, for removal. Seeking RegExp.$ is of course
insufficient.

It's a good idea to read the newsgroup and its FAQ. See below.

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon.co.uk Turnpike v6.05 IE 6
news:comp.lang.javascript FAQ <URL:http://www.jibbering.com/faq/index.html>.
<URL:http://www.merlyn.demon.co.uk/js-index.htmjscr maths, dates, sources.
<URL:http://www.merlyn.demon.co.uk/TP/BP/Delphi/jscr/&c, FAQ items, links.

[g4toloc0]

On Feb 25, 4:06 pm, Dr J R Stockton <[e-mail]>
wrote:

Possibly; but the usage is not given in ISO/IEC 16262. It is deprecated
for javascript, and one should instead index the result of .exec or
.match. See in <URL:http://www.merlyn.demon.co.uk/js-valid.htm>.

uh, it's true. even if using the regexp object like this is so
uncool...
http://developer.mozilla.org/en/docs...cated_Features

Query : I want to find a way of detecting all and only instances of such
deprecated usage on my site, for removal. Seeking RegExp.$ is of course
insufficient.

It's a good idea to read the newsgroup and its FAQ. See below.

mmm. is this a request or are you just quoting a FA Question???

Ciao,
Seba