Develop Reference

Extracting a complicated part of the string with plain Javascript

I have a following string:
Text
I want to extract from this string, with the use of JavaScript 'pl' or 'pl_company_com'
There are a few variables:
jan_kowalski is a name and surname it can change, and sometimes even have 3 elements
the country code (in this example 'pl') will change to other en / de / fr (this is that part of the string i want to get)
the rest of the string remains the same for every case (beginning + everything after starting with _company_com ...
Ps. I tried to do it with split, but my knowledge of JS is very basic and I cant get what i want, plase help

An alternative to Randy Casburn's solution using regex
let out = new URL('https://my.domain.com/personal/jan_kowalski_pl_company_com/Documents/Forms/All.aspx').href.match('.*_(.*_company_com)')[1];
console.log(out);
Or if you want to just get that string with those country codes you specified
let out = new URL('https://my.domain.com/personal/jan_kowalski_pl_company_com/Documents/Forms/All.aspx').href.match('.*_((en|de|fr|pl)_company_com)')[1];
console.log(out);
let out = new URL('https://my.domain.com/personal/jan_kowalski_pl_company_com/Documents/Forms/All.aspx').href.match('.*_((en|de|fr|pl)_company_com)')[1];
console.log(out);
A proof of concept that this solution also works for other combinations
let urls = [
new URL('https://my.domain.com/personal/jan_kowalski_pl_company_com/Documents/Forms/All.aspx'),
new URL('https://my.domain.com/personal/firstname_middlename_lastname_pl_company_com/Documents/Forms/All.aspx')
]
urls.forEach(url => console.log(url.href.match('.*_(en|de|fr|pl).*')[1]))

I have been very successful before with this kind of problems with regular expressions:
var string = 'Text';
var regExp = /([\w]{2})_company_com/;
find = string.match(regExp);
console.log(find); // array with found matches
console.log(find[1]); // first group of regexp = country code
First you got your given string. Second you have a regular expression, which is marked with two slashes at the beginning and at the end. A regular expression is mostly used for string searches (you can even replace complicated text in all major editors with it, which can be VERY useful).
In this case here it matches exactly two word characters [\w]{2} followed directly by _company_com (\w indicates a word character, the [] group all wanted character types, here only word characters, and the {}indicate the number of characters to be found). Now to find the wanted part string.match(regExp) has to be called to get all captured findings. It returns an array with the whole captured string followed by all capture groups within the regExp (which are denoted by ()). So in this case you get the country code with find[1], which is the first and only capture group of the regular expression.

Get string between tags when multiple tags present

Just trying to figure this one out as regex is nowhere near my strong point :(
Basically I'm trying to get the value between bbcode tags: That could look like either of the following:
[center]text[/center]
[left][center]text[/center][/left]
[right][left][center]text[/center][/left][/right]
And currently have this hideous if else block of code to prevent it getting large like the third option above.
if (/\[left\]|\[\/left\]/.test(text[2])) {
// set the value in the [left][/left] tags
text[2] = text[2].match(/\[left\](.*?)\[\/left\]/)[1];
} else if (/\[right\]|\[\/right\]/.test(text[2])) {
// set value in the [right][/right] tags
text[2] = text[2].match(/\[right\](.*?)\[\/right\]/)[1];
} else if (/\[center\]|\[\/center\]/.test(text[2])) {
// set value in the [right][/right] tags
text[2] = text[2].match(/\[center\](.*?)\[\/center\]/)[1];
}
What I'd like to do is shorten it down to a single regex expression to grab that value text from the above examples, I've gotten down to an expression like this:
/\[(?:center|left|right)\](.*?)\[\/(?:center|left|right)\]/
But as you can see in this RegExr demo, it doesn't match what I need it to.
How can I achieve this?
Note
It should only match left|right|center as the selected text could also have various other bbcode tags.
If the string looks like this:
[center][left][img]/link/to/img.png[/img][/left][/center]
I want to get what is between the left|center|right tags which in this case would be:
[img]/link/to/img.png[/img]
More examples:
[center][url=lintosomething.com]LINK TEXT[/url][/center]
Should only get: [url=lintosomething.com]LINK TEXT[/url]
Or
[center]egibibskdfbgfdkfbg sd fgkgb fkgbgk fhwo3g regbiurb geir so go to [url=lintosomething.com]LINK TEXT[/url] and ibgri gbenkenbieurgnerougnerogrnreog erngo[/center]
Wanting:
egibibskdfbgfdkfbg sd fgkgb fkgbgk fhwo3g regbiurb geir so go to [url=lintosomething.com]LINK TEXT[/url] and ibgri gbenkenbieurgnerougnerogrnreog erngo

Edit: Ok, I think this fits your needs.
My regex:
/[^\]\[]*\[(\w+)[=\.\"\w]*\][^\]]+\[\/\1\][^\]\[]*/g
Explanation:
Match 0 or more characters that arent [ or ]
Match a single [
Match 1 or more of alpha characters, we'll use this later as a backreference
Match 0 or more of = . " or alpha characters
Match a single ]
Match 1 or more non [ characters
Match a single [
Match a single /
Match the same characters as step 3. (Our back reference)
Match a single ]
Match 0 or more characters that arent [ or ]
See it in action
However I would like to state that if you're going to be parsing bbcodes you're almost certainly better off just using a bbparser.

Why not just replace all those tags with empty string
var rawString; // your input string
var cleanedString = rawString.replace(~\[/?(left|right|center)\]~, '');

You could use a capturing group like this:
(?:\[\w+\])*(\w+)(?:\[\/\w+\])*
Or with a capture group named "value" like this:
(?:\[\w+\])*(?<value>\w+)(?:\[\/\w+\])*
The first and last groups are non-capturing... (?: ...)
And the middle group is capturing (\w+)
And the middle group if named like this (?<value>\w+)
Note: For simplicity, I replaced your center|left|right values with \w+ but you could swap them back in with no impact.
I use an app called RegExRX. Here's a screenshot with the RegEx and captured values.
Lots of ways you could tweak it. Good luck!

Simple Regexp Pattern matching with escape characters

Hopefully a simple one!
I've been trying to get this to work for several hours now but am having no luck, as I'm fairly new to regexp I may be missing something very obvious here and was hoping someone could point me in the right direction. The pattern I want to match is as follows: -
At least 1 or more numbers + "##" + at least 1 or more numbers + "##" + at least 1 or more numbers
so a few examples of valid combinations would be: -
1##2##3
123#123#123
0##0##0
A few invalid combinations would be
a##b##c
1## ##1
I've got the following regexp like so: -
[\d+]/#/#[\d+]/#/#[\d+]
And am using it like so (note the double slashes as its inside a string): -
var patt = new RegExp("[\\d+]/#/#[\\d+]/#/#[\\d+]");
if(newFieldValue!=patt){newFieldValue=="no match"}
I also tried these but still nothing: -
if(!patt.text(newFieldValue)){newFieldValue==""}
if(patt.text(newFieldValue)){}else{newFieldValue==""}
But nothing I try is matching, where am I going wrong here?
Any pointers gratefully received, cheers!

1) I can't see any reason to use the RegExp constructor over a RegExp literal for your case. (The former is used primarily where the pattern needs to by dynamic, i.e. is contributed to by variables.)
2) You don't need a character class if there's only one type of character in it (so \d+ not [\d+]
3) You are not actually checking the pattern against the input. You don't apply RegEx by creating an instance of it and using ==; you need to use test() or match() to see if a match is made (the former if you want to check only, not capture)
4) You have == where you mean to assign (=)
if (!/\d+##\d+##\d+/.test(newFieldValue)) newFieldValue = "no match";

You put + inside the brackets, so you're matching a single character that's either a digit or +, not a sequence of digits. I also don't understand why you have / before each #, your description doesn't mention anything about this character.
Use:
var patt = /\d+##\d+##\d+/;

You should use the test method of the pat regex
if (!patt.test(newFieldValue)){ newFieldValue=="no match"; }
once you have a valid regular expression.

Try this regex :
^(?:\d+##){2}\d+$
Demo: http://regex101.com/r/mE8aG7
With the following regex
[\d+]/#/#[\d+]/#/#[\d+]
You would only match things like:
+/#/#5/#/#+
+/#/#+/#/#+
0/#/#0/#/#0
because the regex engine sees it like on the schema below:

Something like:
((-\s)?\d+##)+\d+

Replace all besides the Regex group?

I was given a task to do which requires a long time to do.
The image say it all :
This is what I have : (x100 times):
And I need to extract this value only
How can I capture the value ?
I have made it with this regex :
DbCommand.*?\("(.*?)"\);
As you can see it does work :
And after the replace function (replace to $1) I do get the pure value :
but the problem is that I need only the pure values and not the rest of the unmatched group :
Question : In other words :
How can I get the purified result like :
Eservices_Claims_Get_Pending_Claims_List
Eservices_Claims_Get_Pending_Claims_Step1
Here is my code at Online regexer
Is there any way of replacing "all besides the matched group" ?
p.s. I know there are other ways of doing it but I prefer a regex solution ( which will also help me to understand regex better)

Unfortunately, JavaScript doesn't understand lookbehind. If it did, you could change your regular expression to match .*? preceded (lookbehind) by DbCommand.*?\(" and followed (lookahead) by "\);.
With that solution denied, i believe the cleanest solution is to perform two matches:
// you probably want to build the regexps dynamically
var regexG = /DbCommand.*?\("(.*?)"\);/g;
var regex = /DbCommand.*?\("(.*?)"\);/;
var matches = str.match(regexG).map(function(item){ return item.match(regex)[1] });
console.log(matches);
// ["Eservices_Claims_Get_Pending_Claims_List", "Eservices_Claims_Get_Pending_Claims_Step1"]
DEMO: http://jsbin.com/aqaBobOP/2/edit

You should be able to do a global replace of:
public static DataTable.*?{.*?DbCommand.*?\("(.*?)"\);.*?}
All I've done is changed it to match the whole block including the function definition using a bunch of .*?s.
Note: Make sure your regex settings are such that the dot (.) matches all characters, including newlines.
In fact if you want to close up all whitespace, you can slap a \s* on the front and replace with $1\n:
\s*public static DataTable.*?{.*?DbCommand.*?\("(.*?)"\);.*?}
Using your test case: http://regexr.com?37ibi

You can use this (without the ignore case and multiline option, with a global search):
pattern: (?:[^D]+|\BD|D(?!bCommand ))+|DbCommand [^"]+"([^"]+)
replace: $1\n

Try simply replacing the whole document replacing using this expression:
^(?: |\t)*(?:(?!DbCommand).)*$
You will then only be left with the lines that begin with the string DbCommand
You can then remove the spaces in between by replacing:
\r?\n\s* with \n globally.
Here is an example of this working: http://regexr.com?37ic4

Add regex to ignore /js /img and /css

I have this regular expression
// Look for /en/ or /en-US/ or /en_US/ on the URL
var matches = req.url.match( /^\/([a-zA-Z]{2,3}([-_][a-zA-Z]{2})?)(\/|$)/ );
Now with the above regular express it will cause the problem with the URL such as:
http://mydomain.com/css/bootstrap.css
or
http://mydomain.com/js/jquery.js
because my regular expression is to strip off 2-3 characters from A-Z or a-z
My question is how would I add in to this regular expression to not strip off anything with
js or img or css or ext
Without impacting the original one.
I'm not so expert on regular expression :(

Negative lookahead?
var matches = req.url.match(/^\/(?!(js|css))([a-zA-Z]{2,3}([-_][a-zA-Z]{2})?)(\/|$)/ );
\ not followed by js or css

First of all you have not defined what exactly you are searching for.
Define an array with lowercased common language codes (Common language codes)
This way you'll know what to look for.
After that, convert your url to lowercase and replace all '_' with '-' and search for every member of the array in the resulting string using indexOf().

Since you said you're using the regex to replace text, I changed it to a replace function. Also, you forced the regex to match the start of the string; I don't see how it would match anything with that. Anyway, here's my approach:
var result = req.url.replace(/\/([a-z]{2,3}([-_][a-z]{2})?)(?=\/|$)/i,
function(s,t){
switch(t){case"js":case"img":case"css":case"ext":return s;}
return "";
}
);