I want to match only parent domain name from an email address, which might or might not have a subdomain.
So far I have tried this:
new RegExp(/.+#(:?.+\..+)/);
The results:
Input: abc#subdomain.maindomain.com
Output: ["abc#subdomain.domain.com", "subdomain.maindomain.com"]
Input: abc#maindomain.com
Output: ["abc#maindomain.com", "maindomain.com"]
I am interested in the second match (the group).
My objective is that in both cases, I want the group to match and give me only maindomain.com
Note: before the down vote, please note that neither have I been able to use existing answers, nor the question matches existing ones.
One simple regex you can use to get only the last 2 parts of the domain name is
/[^.]+\.[^.]$/
It matches a sequence of non-period characters, followed by period and another sequence of non-periods, all at the end of the string. This regex doesn't ensure that this domain name happens after a "#". If you want to make a regex that also does that, you could use lazy matching with "*?":
/#.*?([^.]+\.[^.])$/
However,I think that trying to do everything at once tends to make the make regexes more complicated and hard to read. In this problem I would prefer to do things in two steps: First check that the email has an "#" in it. Then you get the part after the "#" and pass it to the simple regex, which will extract the domain name.
One advantage of separating things is that some changes are easier. For example, if you want to make sure that your email only has a single "#" in it its very easy to do in a separate step but would be tricky to achieve in the "do everything" regex.
You can use this regex:
/#(?:[^.\s]+\.)*([^.\s]+\.[^.\s]+)$/gm
Use captured group #1 for your result.
It matches # followed by 0 or more instance of non-DOT text and a DOT i.e. (?:[^.\s]+\.)*.
Using ([^.\s]+\.[^.\s]+)$ it is matching and capturing last 2 components separated by a DOT.
RegEx Demo
With the following maindomain should always return the maindomain.com bit of the string.
var pattern = new RegExp(/(?:[\.#])(\w[\w-]*\w\.\w*)$/);
var str = "abc#subdomain.maindomain.com";
var maindomain = str.match(pattern)[1];
http://codepen.io/anon/pen/RRvWkr
EDIT: tweaked to disallow domains starting with a hyphen i.e - '-yahoo.com'
Related
How can I extract only top-level and second-level domain from a URL using regex? I want to skip all lower level domains. Any ideas?
Here's my idea,
Match anything that isn't a dot, three times, from the end of the line using the $ anchor.
The last match from the end of the string should be optional to allow for .com.au or .co.nz type of domains.
Both the last and second last matches will only match 2-3 characters, so that it doesn't confuse it with a second-level domain name.
Regex:
[^.]*\.[^.]{2,3}(?:\.[^.]{2,3})?$
Demonstration:
Regex101 Example
Updated 2019
This is an old question, and the challenge here is a lot more complicated as we start adding new vanity TLDs and more ccTLD second level domains (e.g. .co.uk, .org.uk). So much so, that a regular expression is almost guaranteed to return false positives or negatives.
The only way to reliably get the primary host is to call out to a service that knows about them, like the Public Suffix List.
There are several open-source libraries out there that you can use, like psl, or you can write your own.
Usage for psl is quite intuitive. From their docs:
var psl = require('psl');
// Parse domain without subdomain
var parsed = psl.parse('google.com');
console.log(parsed.tld); // 'com'
console.log(parsed.sld); // 'google'
console.log(parsed.domain); // 'google.com'
console.log(parsed.subdomain); // null
// Parse domain with subdomain
var parsed = psl.parse('www.google.com');
console.log(parsed.tld); // 'com'
console.log(parsed.sld); // 'google'
console.log(parsed.domain); // 'google.com'
console.log(parsed.subdomain); // 'www'
// Parse domain with nested subdomains
var parsed = psl.parse('a.b.c.d.foo.com');
console.log(parsed.tld); // 'com'
console.log(parsed.sld); // 'foo'
console.log(parsed.domain); // 'foo.com'
console.log(parsed.subdomain); // 'a.b.c.d'
Old answer
You could use this:
(\w+\.\w+)$
Without more details (a sample file, the language you're using), it's hard to discern exactly whether this will work.
Example: http://regex101.com/r/wD8eP2
Also, you can likely do that with some expression similar to,
^(?:https?:\/\/)(?:w{3}\.)?.*?([^.\r\n\/]+\.)([^.\r\n\/]+\.[^.\r\n\/]{2,6}(?:\.[^.\r\n\/]{2,6})?).*$
and add as much as capturing groups that you want to capture the components of a URL.
Demo
If you wish to simplify/modify/explore the expression, it's been explained on the top right panel of regex101.com. If you'd like, you can also watch in this link, how it would match against some sample inputs.
RegEx Circuit
jex.im visualizes regular expressions:
For anyone using JavaScript and wanting a simple way to extract the top and second level domains, I ended up doing this:
'example.aus.com'.match(/\.\w{2,3}\b/g).join('')
This matches anything with a period followed by two or three characters and then a word boundary.
Here's some example outputs:
'example.aus.com' // .aus.com
'example.austin.com' // .austin.com
'example.aus.com/howdy' // .aus.com
'example.co.uk/howdy' // .co.uk
Some people might need something a bit cleverer, but this was enough for me with my particular dataset.
Edit
I've realised there are actually quite a few second-level domains which are longer than 3 characters (and allowed). So, again for simplicity, I just removed the character counting element of my regex:
'example.aus.com'.match(/\.\w*\b/g).join('')
Since TLDs now include things with more than three-characters like .wang and .travel, here's a regex that satisfies these new TLDs:
([^.\s]+\.[^.\s]+)$
Strategy: starting at the end of the string, look for one or more characters that aren't periods or whitespace, followed by a single period, followed by one or more characters that aren't periods or whitespace.
http://regexr.com/3bmb3
With capturing groups you can achieve some magix.
For example, consider the following javascript:
let hostname = 'test.something.else.be';
let domain = hostname.replace(/^.+\.([^\.]+\.[^\.]+)$/, '$1');
document.write(domain);
This will result in a string containing 'else.com'. This is because the regex itself will match the complete string and the capturing group will be mapped to $1. So it replaces the complete string 'test.something.else.com' with '$1' which is actually 'else.com'.
The regex isn't pretty and can probably be made more dynamic with things like {3} for defining how many levels deep you want to look for subdomains, but this is just an illustration.
if you want all specific Top Level Domain name then you can write regular expression like this:
[RegularExpression("^(https?:\\/\\/)?(([\\w]+)?\\.?(\\w+\\.((za|zappos|zara|zero|zip|zippo|zm|zone|zuerich|zw))))\\/?$", ErrorMessage = "Is not a valid fully-qualified URL.")]
You can also put more domain name from this link:
https://www.icann.org/resources/pages/tlds-2012-02-25-en
The following regex matches a domain with root and tld extractions (named capture groups) from a url or domain string:
(?:\w+:\/{2})?(?<cs_domain>(?<cs_domain_sub>(?:[\w\-]+\.)*?)(?<cs_domain_root>[\w\-]+(?<cs_domain_tld>(?:\.\w{2})?(?:\.\w{2,3}|\.xn-+\w+|\.site|\.club))))\|
It's hard to say if it is perfect, but it works on all the test data sets that I have put it against including .club, .xn-1234, .co.uk, and other odd endings. And it does it in 5556 steps against 40k chars of logs, so the efficiency seems reasonable too.
If you need to be more specific:
/\.(?:nl|se|no|es|milru|fr|es|uk|ca|de|jp|au|us|ch|it|io|org|com|net|int|edu|mil|arpa)/
Based on http://www.seobythesea.com/2006/01/googles-most-popular-and-least-popular-top-level-domains/
There may be a very simple answer to this, probably because of my familiarity (or possibly lack thereof) of the replace method and how it works with regex.
Let's say I have the following string: abcdefHellowxyz
I just want to strip the first six characters and the last four, to return Hello, using regex... Yes, I know there may be other ways, but I'm trying to explore the boundaries of what these methods are capable of doing...
Anyway, I've tinkered on http://regex101.com and got the following Regex worked out:
/^(.{6}).+(.{4})$/
Which seems to pass the string well and shows that abcdef is captured as group 1, and wxyz captured as group 2. But when I try to run the following:
"abcdefHellowxyz".replace(/^(.{6}).+(.{4})$/,"")
to replace those captured groups with "" I receive an empty string as my final output... Am I doing something wrong with this syntax? And if so, how does one correct it, keeping my original stance on wanting to use Regex in this manner...
Thanks so much everyone in advance...
The code below works well as you wish
"abcdefHellowxyz".replace(/^.{6}(.+).{4}$/,"$1")
I think that only use ()to capture the text you want, and in the second parameter of replace(), you can use $1 $2 ... to represent the group1 group2.
Also you can pass a function to the second parameter of replace,and transform the captured text to whatever you want in this function.
For more detail, as #Akxe recommend , you can find document on https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace.
You are replacing any substring that matches /^(.{6}).+(.{4})$/, with this line of code:
"abcdefHellowxyz".replace(/^(.{6}).+(.{4})$/,"")
The regex matches the whole string "abcdefHellowxyz"; thus, the whole string is replaced. Instead, if you are strictly stripping by the lengths of the extraneous substrings, you could simply use substring or substr.
Edit
The answer you're probably looking for is capturing the middle token, instead of the outer ones:
var str = "abcdefHellowxyz";
var matches = str.match(/^.{6}(.+).{4}$/);
str = matches[1]; // index 0 is entire match
console.log(str);
I had a requirement of parsing a set of urls and extract specific elements from urls under special conditions. To explain it further, consider a set of urls:
http://www.example.com/appName1/some/extra/parts/keyword/rest/of/the/url
http://www.somewebsite.com/appName2/some/extra/parts/keyword/rest/of/the/url
http://www.someothersite.com/appname3/rest/of/the/url
As you can see, there are two sets of urls, one having the word "keyword" in it and others which don't. In my code, I will receive the part of the url after domain name (eg: /appName1/some/extra/parts/keyword/rest/of/the/url).
I have two tasks, one check if the word "keyword" is present in the url, and second, to be done only if "keyword" is not present in url, parse the url to fetch the two groups as the appName and rest of the url (eg: grp 1. appName3 and grp 2. rest/of/the/url for url 3, as it doesn't have "keyword" in it). The whole thing should be done in one regex.
My progress:
I was able to parse the app name and rest of the url into groups, but was not able to apply the condition.
I found out a way to select stings not having "keyword" in it, I'm not sure if it's the right way to do it:^((?!.\*keyword).\*)$
Next, to combine the above two, I tried something I found after a long search, which has syntax (?(?=regex)then|else) Reference. And the result was :
(?(?=^((?!.*keyword).*)$)\1)But it says invalid group structure.
I had gone through many stackoverflow entries and tutorials, but couldn't reach the actual requirement. Please help me solve this.
Yes, this is in fact possible. As far as I understand, you have the following cases:
/appName/some/extra/parts/keyword/rest/of/the/url
/appName/rest/of/the/url
You want your regex to not match the first one at all, while in the second case you want "appName" in one group and "rest/of/the/url" in another. The following regex will do that:
^(?!.*\/keyword\/)\/(.*?)\/(.*)$
Explanation:
^ assert position at the start of the string`
(?!.*\/keyword\/) is a negative lookahead, and looks ahead to make sure the string does not contain /keyword/. This is where the magic happens
\/ matches "/", i.e. the slash right after the domain name
(.*?)\/ captures the first group (appname in your example) greedily until next slash
(.*)$ is the group that captures "rest/of/the/url"
I am trying to test the pathname of the url, checking if pathname starts with privmsg as well as contains one of the words in the selection. And my quantifier is selecting that at least one word must be found.
New RegExp thanks to one of the answers and I extended it more.
var post = /(^\/privmsg\?).+(post|reply){1}(.*)?/;
My urls will look like
/privmsg?mode=post
/privmsg?mode=reply
/privmsg?mode=reply&p=2 //another way
Though we have other modes that I do not want. I need to just get the constant url beginning with privmsg and having at least post or reply in it. Can someone explain what is wrong with my regex string and if I used the quantifier incorrectly.
Problem now is that it is still coming out false...
You need to allow for arbitrary characters between ? and (post|reply) (i.e. mode=). E.g.:
var post = /^\/privmsg\?.+(post|reply){1}/g;
\/
|match any sequence of|
|1 or more characters |
You miss to include something for mode=.
With your regex you will match strings like /privmsg?post.
So alter your regex to include mode=:
^\/privmsg\?.*(post|reply)$
I've seen a number of examples on StackOverflow to get the "second" part of a MIME content type. What I'd like is, when provided with: text/html; charset=ISO-8859-1
I'd like to return just: html
The Regex I've seen thus far has been something like:
/[^text/]*$/
But in my testing, the matched result is just "ml"
I want whatever lies after the "text/" in the string, but for whatever reason all I'm getting is the last two letters. To be clear I consulted a number of other posts including:
Get second part of a string using RegEx
Which I thought would be exactly what I want, but my tests show that regex does not work.Any help would be much appreciated.
edit to broaden up the question. I'm trying to isolate part of the Content-Type returned in the jquery object.
var regex_content = /[^text/]([^;\s]+)/
var contentType = jqXHR.getResponseHeader("Content-Type");
alert(contentType.match(regex_content));
With the regex_content that someone else provided, html,tml is returned if the content type is text/html; charset=ISO-SOMENUMBERS. I'd like to ONLY have html be matched.
Your regex should be:
^text/([^;\s]+)
and capture the first group.
And since threre is a / in your regex, use the new RegExp() constructor:
var re = new RegExp("^text/([^;\\s]+)");
The main problem with your regex is that it ignores the characters t, e, x, and / individually and matches other characters. You want to match the group that follows the / and precedes the ;, so your regex would be
/(?:[^/]*\/)([^;]*)/
This has a non-capturing group ((?:[^/]*/)) match (and ignore) the characters up to the first /, then a capturing group (([^;]*)) to match and keep the text you want before the first ;.