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how to make replace function replace globally in a string



I was trying to use back-to-back replace functions to convert a url:

str1 =
str.replace("%2F","/").replace("%3F","?").replace("%3D","=").replace(" %2
6","&");

It didn't replace all 4 types of strings.

Then, I googled and found this suggestion of some JavaScript Tutorials,
so I used replace with a regex with a global switch:

str1 =
str.replace(/%2F/g,"/").replace(/%3F/g,"?").replace(/%3D/g,"=").replace(
/%26/g,"&");

and it did replace all the occurances of all the strings.

OK. my problem is solved, but I am curious why should the first method
not work?

Thanks.
--

Jul 3 '07 #1
5 8220
Lee
V S Rawat said:
>
I was trying to use back-to-back replace functions to convert a url:

str1 =
str.replace("%2F","/").replace("%3F","?").replace("%3D","=").replace(" %2
6","&");

It didn't replace all 4 types of strings.

Then, I googled and found this suggestion of some JavaScript Tutorials,
so I used replace with a regex with a global switch:

str1 =
str.replace(/%2F/g,"/").replace(/%3F/g,"?").replace(/%3D/g,"=").replace(
/%26/g,"&");

and it did replace all the occurances of all the strings.

OK. my problem is solved, but I am curious why should the first method
not work?
Because there's no "global" flag specified.
Replacing only the first occurrence has been the default behavior
of replacement functions since the beginning of time.
If you're using a string as the first parameter, instead of a RegEx,
you can add an optional third parameter to specify flags:

http://developer.mozilla.org/en/docs...String:replace
--

Jul 3 '07 #2
d d
V S Rawat wrote:
I was trying to use back-to-back replace functions to convert a url:
str1 =
str.replace("%2F","/").replace("%3F","?").replace("%3D","=").replace(" %2
6","&");
Did you not consider str1=unescape(str); ?

~dd
Jul 3 '07 #3
Lee wrote:
V S Rawat said:

I was trying to use back-to-back replace functions to convert a
url:

str1 =
str.replace("%2F","/").replace("%3F","?").replace("%3D","=").repla ce
("%2 6","&");

It didn't replace all 4 types of strings.

Then, I googled and found this suggestion of some JavaScript
Tutorials, so I used replace with a regex with a global switch:

str1 =
str.replace(/%2F/g,"/").replace(/%3F/g,"?").replace(/%3D/g,"=").repl
ace( /%26/g,"&");

and it did replace all the occurances of all the strings.

OK. my problem is solved, but I am curious why should the first
method not work?

Because there's no "global" flag specified.
Replacing only the first occurrence has been the default behavior
of replacement functions since the beginning of time.
If you're using a string as the first parameter, instead of a RegEx,
you can add an optional third parameter to specify flags:

http://developer.mozilla.org/en/docs..._Reference:Glo
bal_Objects:String:replace
Lee wrote:
V S Rawat said:

I was trying to use back-to-back replace functions to convert a
url:

str1 =
str.replace("%2F","/").replace("%3F","?").replace("%3D","=").repla ce
("%2 6","&");

It didn't replace all 4 types of strings.

Then, I googled and found this suggestion of some JavaScript
Tutorials, so I used replace with a regex with a global switch:

str1 =
str.replace(/%2F/g,"/").replace(/%3F/g,"?").replace(/%3D/g,"=").repl
ace( /%26/g,"&");

and it did replace all the occurances of all the strings.

OK. my problem is solved, but I am curious why should the first
method not work?

Because there's no "global" flag specified.
Replacing only the first occurrence has been the default behavior
of replacement functions since the beginning of time.
If you're using a string as the first parameter, instead of a RegEx,
you can add an optional third parameter to specify flags:

http://developer.mozilla.org/en/docs..._Reference:Glo
bal_Objects:String:replace
The following did it. With global flag. To be safer, I added ignore
flag also.

str1 =
str.replace("%2F","/","gi").replace("%3F","?","gi").replace("%3D","=", "g
i").replace("%26","&","gi"))

Thanks.

Actually, I am learning from free ebooks downloaded from net, and most
of them don't bother to give the full syntax. They just give one or two
simple usage of each keyword.

The ebook I am having didn't even tell about using regex in replace.
That I had found on google.

Thanks for pointing me out to mozilla resources.
--
Jul 3 '07 #4
d d wrote:
V S Rawat wrote:
I was trying to use back-to-back replace functions to convert a
url: str1 =
str.replace("%2F","/").replace("%3F","?").replace("%3D","=").repla ce
("%2 6","&");

Did you not consider str1=unescape(str); ?

~dd
Wow!

I wasn't aware of that.

It is the most handy.

Thanks. :-)
--
Jul 3 '07 #5
d d wrote:
>V S Rawat wrote:
>I was trying to use back-to-back replace functions to convert a url:
str1 =
str.replace("%2F","/").replace("%3F","?").replace("%3D","=").replace(" %2
6","&");

Did you not consider str1=unescape(str); ?
It makes more sense to be recommending the ECMA 262 3rd edition
specified global - decodeURIComponent - function for reversing this
style of encoding, as it is part of the language, rather than the
non-standardised - unescape - function, which only may be provided as
part of a browser object model.

Richard.

Jul 3 '07 #6

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