Golang Regexp Reference within MustCompile (Find repeating character) [duplicate] - regex

This question already has answers here:
Regex to match repeated characters
(3 answers)
Closed 6 years ago.
I am having a hard time with Go's regex. It seems it's different than other language, can someone help me on this.
Obj. I want MustCompile to find all repeated characters in the string.
APPLE (where P's repeating)
re := regexp.MustCompile("(\\w)\\${1}\\+")
Above is what I have tried but didn't work at all. Basically I wanted to do:
([A-Za-z])\1+
Can someone tell me what I am doing wrong?
Example below:
https://play.golang.org/p/DeuaIva968

Apparently Golang doesn't supposed back referencing due to efficiency. :(
Thank you everyone for your help.

Related

Regex match repeating pattern [duplicate]

This question already has an answer here:
Reference - What does this regex mean?
(1 answer)
Closed 2 years ago.
I'm trying to match e-mails with a string like:
s.te.e.ve.s.mit.h.p#gmail.com
Effectively I'm after any repeating pattern (of at least 4 times) of a string of characters followed by a period, with the last before the email domain not having a period.
I'm not great with Regex, but so far I've only come up with:
[aA-zZ\.]{4,}[aA-zZ]#.*
This matches what I need, however it also pulls more than I'd like.
Any advice?
Thanks for the help, I see now where I was making the mistake. Wiktor's answer seemed to work the best, though for some reason it would time out in Redshift if I didn't put . in brackets. [.]
The expression which appears to work correctly is:
^([a-zA-Z][.]){4,}[a-zA-Z]#.*

Regex with exactly one space and special characters [duplicate]

This question already has an answer here:
Reference - What does this regex mean?
(1 answer)
Closed 3 years ago.
Unfortunately I found that the existing examples are confusing and not similar enough to what I am trying to achieve. I need a regular expression to find occurencies of strings like
=> Test[a]
where between the special character > and Test there is exactly one space. The word Test can be replaced by any alphabetic string (=> Apple[b] is another example). I have worked out a regex for all except the first part with the block =>.
Can anyone help me?
I managed to find this expression
.(=>) [a-zA-Z]+\[a\]\.
and it works! Thanks everyone.
Try use this regex:
=> \S+
Here Is Demo

How to regex part of a string from and to some certain characters [duplicate]

This question already has an answer here:
Reference - What does this regex mean?
(1 answer)
Closed 3 years ago.
I have the following string and I want to find a proper regex for it, so I can use it in Regular Expression in Jmeter:
DocumentId_123456
The point is that every time the numbers have different length.
so basically I want everything between _ and the end of string.
Please try it, I guess it works in jmeter
DocumentId_(\d+)
Uou can check it here: [https://regex101.com/]

Regex for all strings that contain exactly two occurrences of 'aa'? [duplicate]

This question already has answers here:
Find shortest matches between two strings
(4 answers)
Closed 4 years ago.
This is a simple question of the Theory of Computation.
I don't know nor want the python coded interpretation of this but rather the theoretical answer of the expression.
I have tried my best to figure it out and came up with the below code:
(ab+ba+bb)*. aa.(ab+ba+bb)*.aa.(ab+ba+bb)* + b*.aa.b*.aa.b*
Is it right? Am I forgetting any other case?
Your regex is too complicated and not very flexible (it only works with strings of a and b). A better solution uses negative look-ahead assertions:
^(?:(?!aa).)*aa(?:(?!aa).)*aa(?:(?!aa).)*$
This looks for any length of substring at the start of the string that does not contain aa, then the first aa, and so on.

Regular Expression format meaning of [RegularExpression(#"^[A-Z]+[a-zA-Z''-'\s]*$")] [duplicate]

This question already has an answer here:
Reference - What does this regex mean?
(1 answer)
Closed 7 years ago.
I am new to the regular expression format.
I just read a line of code in MVC data property, which is
RegularExpression(#"^[A-Z]+[a-zA-Z''-'\s]*$"). I spent time in reading RE descriptions on the Internet, but still can not figure out what is the meaning of the part (''-') in the RegularExpression(#"^[A-Z]+[a-zA-Z''-'\s]*$").
Anyone who can give a hint on the (''-') part will be very appreciated.
Thanks.
Yang
[A-Z] means any character between A and Z (according to their character codes)