Others: “Oh god, regexes are so hard to understand!”
Me, an intellectual: writing a code that does the same.
After fixing, now that you are expert, please migrate the regex to our new language.
I found your email address:
(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])HOWD YOU GET MY PASSWORD?!?
Appropriate username.
I was about to ruin your day by finding a valid email address that would be rejected by your regex, but it doesn’t even parse correctly on regex101.com
The only valid regex for email is
.+btwThe argument here is that checking complex validation is a fool’s errand. Yes, you can write a fully validating regex for RFC email. In fact, it should be possible to write a regex shorter than the one that gets passed around since the 90s, because regular expression engines support recursive patterns now. (Part of the reason that old regex is so complicated is because email allows nested comments (which is insane (how insane? (Lisp levels insane)))).
However, it doesn’t get you much of anywhere. What you really want to know is if it’s a valid email or not, and the only way to do that is to send an email to that address with a confirmation. The only point of the regex is to throw away obviously bad addresses. For that, checking that there’s an @ symbol and something for the user and domain portions is sufficient. I’d add needing a dot in the domain portion, but it’s not that important.
Classically, it was argued that emails don’t even need a domain portion when things are done for internal systems, or that internal domains don’t need a tld. In my personal experience, this is rarely done anymore and can be safely ignored. Maybe some very, very old legacy systems, and if you’re working on one of those, then sure. For everyone else, don’t worry about it. You’re probably working on publicly accessible systems, and even if you’re not, most users are going to prefer using their fully spec’d out email address, anyway.
Cool story bro, go argue with the IETF
Why? Do you think nested comments are a good idea?
Deleted by user.
Where did you get that “RFC standard” regex? It doesn’t allow domain names with one component RFC5321
Neither does it allow spaces in quoted string, as per RFC5322
This, 👋@✉️.gg, is already a working email address in most clients and if RFC6532 ever gets accepted, it would be officially recognized as such.
My point isn’t to make your regex bad, just that it doesn’t validate or invalidate an email properly. Nothing stops me from giving you and invalid but syntactically correct email after all.
You have to send an email anyways to verify, so the most you can check is the presence of one @ symbol.
What about
"user@not_domain"? It validates but isn’t valid - there’s no domain part, theis quotedThat’s not something you can determine using a regex.
“user@com” for example could be a perfectly working email.
The right way is to send a verification email in every case.
Does this regex include
"very.(),:;<>[]\".VERY.\"very@\\ \"very\".unusual".example.com
That
\\.part doesn’t look right, but what do I know. Apparently control codes are valid elsewhere, so a literal backslash followed by any character, even a space or a newline, might actually be valid there.“Yeah, my e-mail address is abc, carriage return, three backspaces and a terminal bell at example dot com. … What do you mean your mail program doesn’t support it?”
No My email is
(?:(?:\r\n)?[ \t])*(?:(?:(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t] )+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?: \r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:( ?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\0 31]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\ ](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+ (?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?: (?:\r\n)?[ \t])*))*|(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z |(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n) ?[ \t])*)*\<(?:(?:\r\n)?[ \t])*(?:@(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\ r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n) ?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t] )*))*(?:,@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])* )(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t] )+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*) *:(?:(?:\r\n)?[ \t])*)?(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+ |\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r \n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?: \r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t ]))*"(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031 ]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\]( ?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(? :(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(? :\r\n)?[ \t])*))*\>(?:(?:\r\n)?[ \t])*)|(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(? :(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)? [ \t]))*"(?:(?:\r\n)?[ \t])*)*:(?:(?:\r\n)?[ \t])*(?:(?:(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]| \\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<> @,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|" (?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t] )*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\ ".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(? :[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[ \]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*|(?:[^()<>@,;:\\".\[\] \000- \031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|( ?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*)*\<(?:(?:\r\n)?[ \t])*(?:@(?:[^()<>@,; :\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([ ^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\" .\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\ ]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*(?:,@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\ [\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\ r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\] |\\.)*\](?:(?:\r\n)?[ \t])*))*)*:(?:(?:\r\n)?[ \t])*)?(?:[^()<>@,;:\\".\[\] \0 00-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\ .|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@, ;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(? :[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t])* (?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\". \[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[ ^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\] ]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*\>(?:(?:\r\n)?[ \t])*)(?:,\s*( ?:(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\ ".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*)(?:\.(?:( ?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[ \["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t ])*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t ])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(? :\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+| \Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*|(?: [^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\ ]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*)*\<(?:(?:\r\n) ?[ \t])*(?:@(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[" ()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n) ?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<> @,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*(?:,@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@, ;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t] )*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\ ".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*)*:(?:(?:\r\n)?[ \t])*)? (?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\". \[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*)(?:\.(?:(?: \r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\[ "()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t]) *))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t]) +|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\ .(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z |(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*\>(?:( ?:\r\n)?[ \t])*))*)?;\s*)
Just pop them into regex101 or a similar tool, add sample data, see the mistake, fix the mistake, continue to do other stuff.
Just pop them into regex101 or a similar tool, add sample data,
see the mistake, fix the mistake, continue to do other stuff.it works there, pull hairFTFY
I usually do
# What we are doing (high level) # Why we need regex # Regex step by step # Examples of matches regexAnd I still rewrite it the next time
// abandon all hope ye who commit here (?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])Edith: damit, Not the first to post this abomination
I haven’t laughed so hard in a month. Thank you for that.
I know I’m weird, but I love regex.
Downvoted so that everyone can know I’m cool since I understand regex better than the idiot who made that meme.
I have found chatgpt to be very good at writing regex. I also don’t know how to write regex.
In my experience, it is good at simple to medium complexity regex. For the harder ones it starts being quite useless though, at best providing a decent starting point to begin debugging from.
well, you won’t get better using chatgpt for it
It helps if you break it apart into its component parts. Which is like anything else, really, but we’ve all accepted that regexes are supposed to run together in an unreadable mess. No reason it has to be that way.
If they are Perl regexes, like all regexes are supposed to be, you can have non-semantic whitespace and comments.
But if you are using some system that enforces something different, you are out of luck.
Not necessarily. For just debugging purposes, you can still break them up to help understand them. Even ignoring that, there are options in languages that don’t implement /x.
At my company we store our regex in the database with linebreaks in it, but when it’s actually called to be used those line breaks are stripped out. That way regex that looks for X can all be all on one line and actually readable.
wait… why do you have so many regexes you need to put them in a database???
My job is regex.
Ummmmmmmm
The comments flag needs more support.
Me checking my own docs: “this is some voodoo shit, idk how it works”
That’s what my comments say
Regexr.com is my go-to.
This is the one I use! Might have to look at regexer though
LOL yeah that’s about right.
Never debug regex, just generate a new one. It’s not worth the hassle to figure out not only what it does, but what it was meant to do.
Better yet, just write it out in code, and never use regex. Tis a stupid thing that never should have been made.
Hard disagree. The function regex serves in programs like Notepad++ can’t be easily replaced by “writing it out in code”. With a very small number of characters you can get complex search patterns and capturing groups. It’s hard to read but incredibly useful.
Can’t upvote twice, have a low effort comment instead
I fall in the abandon it camp. Code is read way more times than it is written. I’d rather read an algorithm that validates input than read a regex that validates input.
You’re discussing a completely different use case from what I said. RegEx can be increidbly useful but it’s not always the only/best option.
feel like thats a notepad++ problem? in general, breaking it out into manageable human ingest-able chunks is A Good Idea
If you’re needing that level of complexity in a text file search, you already fucked up by putting the data in a text file. There’s a reason data file formats exist.
Not even close. Sometimes you can have a large text file where you need to do a find replace with a pattern. For example, in the translation world this can be a common occurrence for translation files (.xliff) or translation memories (.tmx).
There’s a reason why this is widely used and it’s not because everyone else but you is dumb.
Turns out the million hours of coding put into SQL, makes it a better option than regex, even for xml based files.
Maybe for your very specific use case that’s true. However, other use cases exist and for many of those RegEx is the better option.
I’m saying if your use case makes regex the best option, you’ve gone the wrong way and should turn back. There are definitely corners you can paint yourself into that make it the way to go, but you’ve ended up there through a series of bad ideas.
Maybe, just maybe, the context in which you use regex isn’t the same as everyone elses. But hey, who am I to deny you the disservice of thinking you’re the center of the world?
Why would I use SQL to to reformat a poorly structured log file for programs whose source I have no input in during a live debug with a customer on system that I don’t own and can’t install anything on? Or to extract and format things like hosts from a similar file?
That’s stuff that’s quickly and easily done in vim (which is generally part of the base install) with regex. There’s a lot of use cases that have no overlap with SQL.
So your use cases for regex are when you’re not going to actually fix the problem that caused you to need regex?
Modifying software that might not be within the scope of the company that I work for, much less my team, on systems that I explicitly do not have authorization to make such changes on? No, I would not be doing that.
An important thing to remember is that going all-in on a given tool is going to result in a bad time. You suggestion of SQL, for example, excels in querying and modifying data that lives in a database and follows the expected structures in said database. Most data is not in databases, nor is it structured in a compatible manner, if at all. The workarounds needed to coax SQL into performing such tasks would result in syntax both more arcane and more verbose than the regex necessary to transform it into something compatible.
Use the right tool for the right job. For transforming semi-structured and unstructured data into something useful in a practical amount of time, regex is frequently the right tool.
Regex is a write only language.
I love regex and I use it a lot, but I very rarely use it in any kind of permanent solution. When I do, I make sure to keep it as minimal as possible, supplementing with higher level programming where possible. Backreferences and assertions are a cardinal sin and should never be used.
If I have a complex regular expression to code into my app, I write it in pomsky, then copy paste the compiled regex to my source file, but also keep the pomsky source nearby. Much more maintainable.
Aziz! LIGHT!
