Develop Reference

how to find last occurrence of a parent in a given below string [duplicate]

This question already has answers here:
Regex Last occurrence?
(7 answers)
Closed 3 months ago.
I have a below pattern string.
'GP0|#92ca7467-4c0d-461a-aac4-2bc8fd9ee16a;L0|#092ca7467-4c0d-461a-aac4-2bc8fd9ee16a|Analysts;GTSet|#7fa22453-62b1-4bec-b73d-01ccf115d558;GPP|#fd613617-ba9d-43e5-9990-95f96f94af2a;GPP|#ba395283-6169-4c6d-84d5-1cecb3c2a73b;GP0|#a547b95c-0dfa-4f42-b540-e55872fb2e81;L0|#0a547b95c-0dfa-4f42-b540-e55872fb2e81|Awards;GP0|#c4363ae8-8608-4309-92f0-5079c69b47e4;L0|#0c4363ae8-8608-4309-92f0-5079c69b47e4|Digital Workplace;GP0|#1976b988-a993-4f13-a1e8-d847138eebc6;L0|#01976b988-a993-4f13-a1e8-d847138eebc6|Intranet;GP0|#a68218df-b9e8-4f07-bfff-22cab83bbc0d;L0|#0a68218df-b9e8-4f07-bfff-22cab83bbc0d|Microsoft;GP0|#57737444-1a1b-4c87-a479-1548b58e44e3;L0|#057737444-1a1b-4c87-a479-1548b58e44e3|Research;'
I want to get last occurrence of the pattern which starts with GPP and ends with ;
expected output: GPP|#ba395283-6169-4c6d-84d5-1cecb3c2a73b;
I tried this regex /GPP\|.+?;/i but it gives the first occurrence i.e. GPP|#fd613617-ba9d-43e5-9990-95f96f94af2a;

As they come after each other, you can match the pattern and assert that there is no following occurrence starting with the same pattern:
As the match ends on a single character, you can match any character except ; instead using a negated character class.
\bGPP\|[^;]+;(?!GPP\|[^;]+;)
Regex demo

What is this regex: /^\D(?=\w{5})(?=\d{2})/ is not matching "bana12"? [duplicate]

This question already has an answer here:
Reference - What does this regex mean?
(1 answer)
Closed 2 years ago.
The objective is to match strings that are greater than 5 characters long, do not begin with numbers, and have two consecutive digits. I thought my regex was enough to do that but is not matching "bana12".
This regex does the job:
var pwRegex = /^\D(?=\w{5})(?=\w*\d{2})/;
Is not this regex more restrictive than mine? Why do I have to specify that the two or more digits are preceded by zero or more characters?

It is less restrictive than yours.
After the \D, there are 2 lookaheads. For your regex, they are
(?=\w{5})(?=\d{2})
This means that the thing after the non-digit must satisfy both of them. That is,
there must be 5 word characters immediately after the non-digit, and
there must be 2 digits immediately after the non-digit.
There is ana12 immediately after the non digit in the string. an is not 2 digits, so your regex does not match.
The working regex however has these two lookaheads:
(?=\w{5})(?=\w*\d{2})
It asserts that there must be these two things immediately after the \D:
5 word characters, and
a bunch of word characters, followed by two digits
ana12 fits both of those descriptions.
Try this Regex101 Demo. Look at step 6 in the regex debugger. That is when it tries to match the second lookahead.

You were on the right track to maybe use lookaheads, and also with the correct start of your pattern, but it is missing a few things. Consider this version:
^\D(?=.*\d{2})\w{4,}$
Here is an explanation of the pattern:
^ from the start of the string
\D match any non digit character
(?=.*\d{2}) then lookahead and assert that two consecutive digits occur
\w{4,} finally match four or more word characters (total of 5 or more characters)
$ end of the string
The major piece missing from your current attempt is that it only matches one non digit character in the beginning. You need to provide a pattern which can match 5 or more characters.

Regex string without double letter [duplicate]

This question already has answers here:
How can I find repeated characters with a regex in Java?
(3 answers)
Closed 4 years ago.
My question is what can be a valid regex for strings that don't contain a double letter.
My solution is : b(ab)*a + a(ba)*b .
But i don't think it is correct, because it doesn't include the a or b.
Can someone help me?

You can achieve this with a negative lookahead:
const re = /^(?!.*?(.).*?\1)[a-z]*$/g;
let s1 = "abcdefgh", s2 = "abcdefga";
console.log(re.test(s1));
console.log(re.test(s2));
How it works:
/^(?!.*?(.).*?\1)[a-z]*$/g
^ asserts position at start of the string
Negative Lookahead (?!.*?(.).*?\1): Assert that the Regex below does not match
.*? matches any character (except for line terminators)
*? Quantifier — Matches between zero and unlimited times, as few times as possible, expanding as needed
1st Capturing Group (.)
. matches any character (except for line terminators)
.*? matches any character (except for line terminators)
*? Quantifier — Matches between zero and unlimited times, as few times as possible, expanding as needed
\1 matches the same text as most recently matched by the 1st capturing group
Match a single character present in the list below [a-z]*
* Quantifier — Matches between zero and unlimited times, as many times as possible, giving back as needed (greedy)
a-z a single character in the range between a (index 97) and z (index 122) (case sensitive)
$ asserts position at the end of the string, or before the line terminator right at the end of the string (if any)
Global pattern flags
g modifier: global. All matches (don't return after first match)

Regex- match third character [duplicate]

This question already has answers here:
How to match all characters after nth character with regex in JavaScript?
(2 answers)
Closed 5 years ago.
For example, this is my string "RL5XYZ" and I want to check the third character is it 5 or some other number.
I would like to do this with the Regex, without substring.

If you're trying to check whether the third character of a string is a number, you can use the following regex:
/^..[0-9]/
^ Means the match must occur at the start of the string
. Means match any character (we do this twice)
[0-9] Means match a number character in the range 0-9. You can actually adjust this to be a different range.
You can also condense the . using the following notation
/^.{2}[0-9]/
The number in braces basically means repeat the previous operator twice.
You can also rewrite the character set [0-9] as \d.
/^.{2}\d/
To match in JS, simple call exec against the pattern you've created:
/^.{2}\d/.exec('aa3') // => ["aa3", index: 0, input: "aa3"]
/^.{2}\d/.exec('aaa') // => null

If its always going to be checking for the existence of two characters followed by a 5 which is then followed by something else then you could simply check
/..5*/
if you want to get the third character (assuming its always a digit) then you could use.
/..(\d)*/
You'll get results back from regEx like this:
Match 1
Full match 0-3 `RL5`
Group 1. 2-3 `5`
Match 2
Full match 3-5 `XY`

If you want to check if the third character is a digit you can use
.{2}\d.*
But . matches everything so maybe you prefer:
\w{2}\d\w*
\w{2} means any of this [a-zA-Z0-9_] two times.
\d means any digit
\w* means any of [a-zA-Z0-9_] zero or multiple times

var input = 'RL5XYZ';
var position = 3;
var match = '5';
position--;
var r = new RegExp('^[^\s\S]{'+position+'}'+match);
console.log(input.match(r));
position to check where is to find and match what to find
edit: I forgot a ^

Regex pattern to match this string [duplicate]

This question already has answers here:
regex pattern to match a type of strings
(4 answers)
Closed 8 years ago.
I need to match the below type of strings using a regex pattern in javascript.
E.g. /this/<one or more than one word with hyphen>/<one or more than one word with hyphen>/<one or more than one word with hyphen>/<one or more than one word with hyphen>
So this single pattern should match both these strings:
1. /this/is/single-word
2. /this/is more-than/single/word-patterns/to-be-matched
Only the slash (/)and the 'this' in the beginning are consistent and contains only alphabets.

Try this -
^\/this(?:\/[\w\- ]+)+$
Demo here

There are some inconsistencies in your question, and it's not quite clear exactly what you want to match.
That being said, the following regex will provide a loose starting point for the exact strings that you want.
/this/(?:[\w|-]+/?){1,10}
This assumes the ' ' in your url was not intentional. This example will match a url with '/this/' + 1 to 10 additional '/' chunks.
(?:) -> non-matching group
[\w|-]+ -> one or more word characters or a hyphen
/? -> zero or one slashes
{1,10} -> 1 to 10 of the previous element, the non-matching group