
RegExr - tosh
https://regexr.com/
======
irrational
My favorite is [https://regex101.com/](https://regex101.com/)

But I've found all of the following to be useful:

[http://regexone.com/](http://regexone.com/)

[http://www.regexpal.com/](http://www.regexpal.com/)

[http://www.rexegg.com/](http://www.rexegg.com/)

[http://regexr.com/](http://regexr.com/)

[https://www.debuggex.com/](https://www.debuggex.com/)

[https://regexper.com/](https://regexper.com/)

[https://www.regular-expressions.info/](https://www.regular-expressions.info/)

[http://www.cheatography.com/davechild/cheat-
sheets/regular-e...](http://www.cheatography.com/davechild/cheat-
sheets/regular-expressions/)

[http://eloquentjavascript.net/09_regexp.html](http://eloquentjavascript.net/09_regexp.html)

[http://www.smashingmagazine.com/2009/06/essential-guide-
to-r...](http://www.smashingmagazine.com/2009/06/essential-guide-to-regular-
expressions-tools-tutorials-and-resources/)

[http://www.smashingmagazine.com/2009/05/introduction-to-
adva...](http://www.smashingmagazine.com/2009/05/introduction-to-advanced-
regular-expression)

[https://developer.mozilla.org/en-
US/docs/Web/JavaScript/Guid...](https://developer.mozilla.org/en-
US/docs/Web/JavaScript/Guide/Regular_Expressions)

[http://codylindley.com/techpro/2013_05_14__javascript-
regula...](http://codylindley.com/techpro/2013_05_14__javascript-regular-
expression-/)

~~~
lpellis
And for python this one is nice: [https://pythex.org/](https://pythex.org/)

~~~
ehsankia
Regex101 let's you switch mode, and has a python regex one.

------
jasode
I prefer regex101.com because that site assigns _different colors_ to
different capture groupings. I made a previous comment on this and why it's
helpful:
[https://news.ycombinator.com/item?id=9581692](https://news.ycombinator.com/item?id=9581692)

(For some reason RegExr.com is submitted to HN much more often than
regex101.com. Is there a compelling advantage to RegExr that I've overlooked?)

~~~
United857
regexr is open source, unlike regex101.

~~~
Toury2d
That doesn't make it better.

------
goerz
The problem I have with all of these regex websites and tools is that they
usually only use the regex dialect of whatever language they’re written in. Or
at best, a very incomplete list of dialects. Subtle differences between
dialects matter a lot. Personally, I would need at least Perl, Python, GNU
utils (with and without -E), BSD utils (or whatever comes with macOS, again
with and without-E), and vim with the various settings for “magic”. Ideally,
they would also be able to convert between all these dialects.

~~~
LameRubberDucky
If you were on Windows, you could try RegexBuddy. It supports regex dialects
for: .NET, Boost (C++), Delphi, Groovy, Oracle Database, PowerShell, R,
std::regex, VB6, wxWidgets, C#, MySQL, PHP, PostgreSQL, VBScript, Java, Perl,
PCRE, JavaScript, Python, Ruby, Tcl ARE, POSIX BRE, POSIX ERE, GNU BRE, GNU
ERE, XML Schema, and XPath. It will even generate code snippets for you based
on the regex you create with the tool. It can also convert between these
dialects and lets you know if features in the target dialect are not
available.

I am not associated with this company in any way, just a long time user.

~~~
goerz
That does look impressive! I'm tempted to check how well this runs in Wine
(since I'm not a Windows user)

------
dang
Posted many times but the large threads are:

2017
[https://news.ycombinator.com/item?id=13599952](https://news.ycombinator.com/item?id=13599952)

2015
[https://news.ycombinator.com/item?id=9581225](https://news.ycombinator.com/item?id=9581225)

2014
[https://news.ycombinator.com/item?id=7537189](https://news.ycombinator.com/item?id=7537189)

Already in 2008 the comments were listing others:
[https://news.ycombinator.com/item?id=277657](https://news.ycombinator.com/item?id=277657)

------
tabtab
I find RegEx's a bit cryptic. Sure, with enough practice one can read them,
but I'd like an alternative that can easily break out chunks as named units.
One can then reference the named units to compose new named units. Divide-and-
Conquer.

I'd like to see experiments in alternatives that provide this. It could help
do for RegEx's what SQL's WITH statement did for long SQL statements.

Backus–Naur Form could act as a starting point, but it needs some syntactic
adjustments to make it more compact and practical, in my opinion. Partial
example:

    
    
         Side = VarFunc + Segment*;
         Segment = 
             ":" + Varfunc
          | (":" + VarFunc)[0..1] + "{" + "}"
          | (":" + Varfunc)[0..1] + "{" + Base + (";" + Base)* + "}";
         Letter = ('a'..'z'|'A'..'Z');
         ForbiddenChar = $anyChr("/?#%");
         /*
         Legend:
           [x..y] = quantity of repeats (substitute letters with integers)
           [0..n] = zero, one, or multiple
           * = shorthand for [0..n]
           | = "or"
           + = concatenation, ignores white-space
           ++ = concatenation, excludes white space
           +w+ = concatenation, must have white-space between
           'x'..'y' = character falls within range
           $x() = special function or constant, where "x" is a name.
         */

~~~
earenndil
Look at perl6 grammars.

~~~
tabtab
It looks extensive, but perhaps may be overkill for a common regex
alternative. Thanks for the tip, though. A standard or semi-standard would
have to start simple.

------
janpot
I usually prefer [https://regexper.com/](https://regexper.com/). Especially
when trying to make sense of regexes I come across in code I didn't write.

------
mattupstate
I've been using this website for years. It's been so long now that I can't
even remember when Grant Skinner, the former Flash/ActionScript guru, released
it. Nice to see it shared here.

------
jedberg
Why is there a sudden explosion of posts about regex in the last few days? Did
something newsworthy happen that I missed, or is it more of a "I saw the post
last week and then found this cool related thing" bandwagon effect?

~~~
LeonB
I thinks it’s the latter.

If there _is_ a major news item involving regular expressions, we’re all ready
to pounce, ala: [https://xkcd.com/208/](https://xkcd.com/208/)

------
ollerac
This is nice, but my go to tool is:
[https://www.debuggex.com/](https://www.debuggex.com/)

Not only does it tell you what everything means, but it visually displays it
in a way that just makes sense.

~~~
zamadatix
This is always the one I forget about and have a hard time finding. It's not
really great for editing but it's probably the best display I've seen in
regards to debugging large regex.

------
proactivesvcs
I can highly recommend the following tool: Mastering Regular Expressions by
Jeffrey Friedl
[http://shop.oreilly.com/product/9780596528126.do](http://shop.oreilly.com/product/9780596528126.do)

I found the pacing to be excellent, with complimentary exercises and that it
was educational as both a cheatsheet and a coherent text. Learned a lot from
it, despite being experienced from the outset.

------
ekzy
For ruby regex, I use [https://rubular.com/](https://rubular.com/)

Actually I use it for all platforms, and it works most of the time. If I
notice that something is odd because the regex engine is different, then I'll
use something else. But I really value Rubular's UI simplicity.

------
err4nt
Beautiful! I tried it with a particularly nasty regex from a codebase I had
and it did a fantastic job explaining what it would target. It's similar to
regex101.com in a lot of ways, but the UI might be a little more easy to read
and understand.

------
KenanSulayman
Something I can recommend to both experienced and "new developers" alike is
[https://regexper.com](https://regexper.com).

It generates clear graphs from regular expressions making immediately clear
what they do.

------
pcr910303
I love this tool. I have customized Emacs keybindings that open RegExr in a
xwidget-webkit instance, type in regexes, and exit RegExr with the regex
inserted at the cursor.

Great for reading monstrous regexes or sharpening my regex skills.

------
yboris
This is always my go-to tool when I'm trying out RegEx!

~~~
rudiv
Same, I'm a big fan.

------
throwaway5389
One thing that's always perplexed me is the variants of regex and their
differences - is there any write up that defines the majority of them?

------
x4nt
Been using RegExr for years!

~~~
tabs_masterrace
Me too! I have to admit I'm really bad at it and can never remember how the
heck regular expressions work, but whenever I have to come up with something I
just fiddle around in RegExr until it works. Documentation in the sidebar is
super handy too.

------
boomskats
regex101.com lets me have client-side validation without requiring a network
connection, so it's way more useful to me than regexr (although the regexr UI
is nice and I like their github repo).

------
svnpenn
doesnt support POSIX character classes.

this should be preferred over `a-z` as the latter relies on users locale.

