Develop Reference

Javascript Regex match everything after last occurrence of string

I am trying to match everything after (but not including!) the last occurrence of a string in JavaScript.
The search, for example, is:
[quote="user1"]this is the first quote[/quote]\n[quote="user2"]this is the 2nd quote and some url https://www.google.com/[/quote]\nThis is all the text I\'m wirting about myself.\n\nLook at me ma. Javascript.
Edit: I'm looking to match everything after the last quote block. So I was trying to match everything after the last occurrence of "quote]" ? Idk if this is the best solution but its what i've been trying.
I'll be honest, i suck at this Regex stuff.. here is what i've been trying with the results..
regex = /(quote\].+)(.*)/ig; // Returns null
regex = /.+((quote\]).+)$/ig // Returns null
regex = /( .* (quote\]) .*)$/ig // Returns null
I have made a JSfiddle for anyone to have a play with here:
https://jsfiddle.net/au4bpk0e/

One option would be to match everything up until the last [/quote], and then get anything following it. (example)
/.*\[\/quote\](.*)$/i
This works since .* is inherently greedy, and it will match every up until the last \[\/quote\].
Based on the string you provided, this would be the first capturing group match:
\nThis is all the text I\'m wirting about myself.\n\nLook at me ma. Javascript.
But since your string contains new lines, and . doesn't match newlines, you could use [\s\S] in place of . in order to match anything.
Updated Example
/[\s\S]*\[\/quote\]([\s\S]*)$/i
You could also avoid regex and use the .lastIndexOf() method along with .slice():
Updated Example
var match = '[\/quote]';
var textAfterLastQuote = str.slice(str.lastIndexOf(match) + match.length);
document.getElementById('res').innerHTML = "Results: " + textAfterLastQuote;
Alternatively, you could also use .split() and then get the last value in the array:
Updated Example
var textAfterLastQuote = str.split('[\/quote]').pop();
document.getElementById('res').innerHTML = "Results: " + textAfterLastQuote;

regular expression not matching on javascript but matches on other languages

so I've been running around regexp for a while now, and been using RegEx101 to test my patterns, and it never failed (yet).
So I am trying to replace android Emojicons strings to their appropriate HTML image tage via regex, the code seems to match without an issue in the site above, and even works with PHP, but somehow, it doesn't match at all in javascript... so here is my code:
function loadEmojisInMessage(message) {
var regExp = /({emoji:(.*?)})/g; //var regExp = new RegExp("({emoji:(.*?)})","g");
message.replace(regExp, '<img src="emojis/emoji_$2.png" id="$2" class="emojicon" />').toString();
return message;
}
at first I thought I am doing something wrong, so I changed the code to this, just for testing
function loadEmojisInMessage(message) {
var regExp = /({emoji:(.*?)})/g; //var regExp = new RegExp("({emoji:(.*?)})","g");
message.replace(regExp, 'test?').toString();
return message;
}
but even this does not replace at all! (my thought is that it is having an issue matching the pattern in the string :/ )
example strings to match :
{emoji:em_1f50f}
What I am trying to do here is replace the entire string (above) with image HTML tag, while using the second match [it is the second bracket () ] for the URL string
Best Regards
UPDATE :
I forgot to add first matching bracket, sorry!
Also, you can test the pattern here

You're not assigning the result of the replace() method call back to the variable message. If you don't to this, message remains unchanged.
message = message.replace(regExp, '<img src="emojis/emoji_$2.png" id="$2" class="emojicon" />');

Javascript RegExp matching returning too many

I need to take a string and get some values from it. I have this string:
'tab/tab2/tab3'
The '/tab3' is optional so this string should also work:
'tab/tab2'
I currently am trying this which works for the most part:
'tab/tab2/tab3'.match(new RegExp('^tab/([%a-zA-Z0-9\-\_\s,]+)(/([%a-zA-Z0-9-_s,]+)?)$'));
This will return:
["tab/tab2/tab3", "tab2", "/tab3", "tab3"]
but I want it to return
["tab/tab2/tab3", "tab2", "tab3"]
So I need to get rid of the 3rd index item ("/tab3") and also get it to work with just the 'tab/tab2' string.
To complicate it even more, I only have control over the /([%a-zA-Z0-9-_s,]+)? part in the last grouping meaning it will always wrap in a grouping.

you don't need regex for this, just use split() method:
var str = 'tab/tab2/tab3';
var arr = str.split('/');
console.log(arr[0]); //tab
console.log(arr[1]); //tab2
jsfiddle

I used this regexp to do this:
'tab/tab2/tab3'.match(new RegExp('^tab/([%a-zA-Z0-9\-\_\s,]+)(?:/)([%a-zA-Z0-9-_s,]+)$'));
Now I get this return
["tab/tab2/tab3", "tab2", "tab3"]
Now I just need to allow 'tab/tab2' to be accepted aswell...

Do not put regex between " or ', using /g to make global search else only first occurrence is returned
"tab/tab2/tab3".match(/tab[0-9]/g)

javascript regex to extract the first character after the last specified character

I am trying to extract the first character after the last underscore in a string with an unknown number of '_' in the string but in my case there will always be one, because I added it in another step of the process.
What I tried is this. I also tried the regex by itself to extract from the name, but my result was empty.
var s = "XXXX-XXXX_XX_DigitalF.pdf"
var string = match(/[^_]*$/)[1]
string.charAt(0)
So the final desired result is 'D'. If the RegEx can only get me what is behind the last '_' that is fine because I know I can use the charAt like currently shown. However, if the regex can do the whole thing, even better.

If you know there will always be at least one underscore you can do this:
var s = "XXXX-XXXX_XX_DigitalF.pdf"
var firstCharAfterUnderscore = s.charAt(s.lastIndexOf("_") + 1);
// OR, with regex
var firstCharAfterUnderscore = s.match(/_([^_])[^_]*$/)[1]
With the regex, you can extract just the one letter by using parentheses to capture that part of the match. But I think the .lastIndexOf() version is easier to read.
Either way if there's a possibility of no underscores in the input you'd need to add some additional logic.

assign matched values from jquery regex match to string variable

I am doing it wrong. I know.
I want to assign the matched text that is the result of a regex to a string var.
basically the regex is supposed to pull out anything in between two colons
so blah:xx:blahdeeblah
would result in xx
var matchedString= $(current).match('[^.:]+):(.*?):([^.:]+');
alert(matchedString);
I am looking to get this to put the xx in my matchedString variable.
I checked the jquery docs and they say that match should return an array. (string char array?)
When I run this nothing happens, No errors in the console but I tested the regex and it works outside of js. I am starting to think I am just doing the regex wrong or I am completely not getting how the match function works altogether

I checked the jquery docs and they say that match should return an array.
No such method exists for jQuery. match is a standard javascript method of a string. So using your example, this might be
var str = "blah:xx:blahdeeblah";
var matchedString = str.match(/([^.:]+):(.*?):([^.:]+)/);
alert(matchedString[2]);
// -> "xx"
However, you really don't need a regular expression for this. You can use another string method, split() to divide the string into an array of strings using a separator:
var str = "blah:xx:blahdeeblah";
var matchedString = str.split(":"); // split on the : character
alert(matchedString[1]);
// -> "xx"
String.match
String.split