Replacing special characters from a URL

punitpawar has asked for the wisdom of the Perl Monks concerning the following question:

Hello,
Wanted to know if there is any generic way using the replacement operator to get rid of special characters or numbers from a url ?
for eg :

$str="www.abc%20.com"
[download]

I want to get rid of %20 from the url , so the url should be

www.abc.com
[download]

I tried doing

$str = s/%20//;
[download]

this worked for me. But I want a more generic approach.

So I did something like this below, but that got rid of '.' as well.

$str =~ s/(\d+|\W+)//g;
[download]

output

wwwabccom
[download]

Is there a way I can add an exception in my replace command that will say replace all special characters excetp '.' ?

Comment on Replacing special characters from a URL Select or Download Code

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Re: Replacing special characters from a URL by 1nickt (Canon) on Feb 17, 2016 at 19:19 UTC
Hi punitpawar, You may not need to create a pattern by hand. In Perl, usually a tool has already been created for any common task you need to accomplish. Please see URI::Escape. I don't know how your URL domain name got spaces in it, but you might be able to use `URI::Escape::uri_unescape` either before this point in your program, or here, to help you keep/get them out: `perl -MURI::Escape -E ' my $str = "www.abc%20.com"; say $str; $str = URI::Escape::uri_unescape( $str ); say $str; $str =~ s/\s//g; say $str; '` [download] Output: `www.abc%20.com www.abc .com www.abc.com` [download] Hope this helps! The way forward always starts with a minimal test.	[reply] [d/l] [select]
Re: Replacing special characters from a URL by choroba (Cardinal) on Feb 17, 2016 at 18:45 UTC
Please, use `<code>...</code>` tags for better readability. `\W` is non-word, so it's equivalent to `[^\w]` . Just add the dot there: `$str =~ s/[^\w.]\|\d//g;` [download] ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7**2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l] [select]
Re^2: Replacing special characters from a URL by punitpawar (Sexton) on Feb 17, 2016 at 19:23 UTC
Great !!! Thanks a lot !!!	[reply]
Re: Replacing special characters from a URL by kennethk (Abbot) on Feb 17, 2016 at 22:12 UTC
1nickt is right about using URI::Escape. So, you should do that. Also, this sounds a lot like an XY Problem, so why are you trying to do this? In any case, if you wanted to hand-roll a decoding for Percent encoding, you could do it with: `s/%([0-9a-f]{2})/chr hex $1/ieg;` [download] Documentation: chr, hex, Modifiers from perlre. Note that percent encoding is in hex, not decimal, so you probably want to include A-F in some way. #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.	[reply] [d/l]
Re: Replacing special characters from a URL by Your Mother (Archbishop) on Feb 17, 2016 at 19:19 UTC
`%20` is a valid URI part in most of the URI so it sounds like you have broken data. There is no generic substitution or treatment that can fix it unless the breakage is regular and predictable which is impossible to guess from your pseudo-sample. With more information about what your data really looks like, you'll likely get better suggestions.	[reply] [d/l]