Regex Cheatsheet
Dev tools
regex reference
SHOW HN2020
499points
129comments
#53of 3,028 in 2020
Top 2%of 2020 by points
How HN took it
DebatedReal support and real criticism
11 positive, 6 neutral or asking, 1 mixed, 13 critical, out of 31 comments about the project. Thread score -0.03.
Execution: 0 for, 8 againstDesign: 4 for, 0 againstDocs: 2 for, 1 againstIdea: 1 for, 1 against
The thread, comment by comment
Each row is a top-level comment and its replies, in HN's order. Select a cell to open that comment on HN.
positive neutral or mixed critical about another commenter or something else the maker
What HN said
What people liked
Railroad diagrams help understand what an expression does
From 3 comments
I'm loving the graphs which for the first time in years are giving me an idea of what an expression is actually doing. Just because the visualization is kept in a form that is…
__tk__ on HNI love regex and have no trouble reading them, but still love this tool, great job. I especially like the railroad diagrams, for those cases where I brainfarted on a regex and…
StavrosK on HNThis is awesome! Thank you! I hate regex, too, but I love your inline railroad diagramming tool.
mimixco on HN
Good concise tool
From 2 comments
Good tool
shawnyou on HNThis is very neat, thank you!
samat on HN
Objections
Several regexes are wrong or misleading, such as email and IPv6 patterns
From 3 comments
This is really cool! 2 points: 1. it fiddled with my back button which is a bit annoying 2. a better email sample is ``` ^[^@]+@[^@]+\.[^@]+$ ``` which removes the 2 ampersands…
kitd on HNFor the love of god, PLEASE DON’T USE REGEX TO VALIDATE EMAIL. The RegEx of this website ignores plus-addressing, for example. All you need to do to validate email is send a…
Diti on HNThere is no way I would just plop that IPv6 regex into any serious program. :)
kazinator on HN
Only supports JavaScript flavour, flavour not stated clearly
From 2 comments
neat site! clicking an example opens up a playground with live update and explanation and railroad diagrams, similar to sites like regex101[1] and regulex[2] one suggestion would…
asicsp on HNYou're totally right. Right now this tool only supports the javascript flavor of regex. That said, for all the simple expressions shown there it's more or less the same for most…
geongeorgek on HN
Back button behaviour is broken
From 1 comment
This is really cool! 2 points: 1. it fiddled with my back button which is a bit annoying 2. a better email sample is ``` ^[^@]+@[^@]+\.[^@]+$ ``` which removes the 2 ampersands…
kitd on HN
Requests
Support other regex flavours and document differences
From 2 comments
OK, these kinds of regex tools get posted quite often. I get it, regex is very confusing at first. And some of these use-cases result in rather complex expressions nobody should…
robert_tweed on HNneat site! clicking an example opens up a playground with live update and explanation and railroad diagrams, similar to sites like regex101[1] and regulex[2] one suggestion would…
asicsp on HN
Add more content and crowdsourced regexes
From 2 comments
I'm glad you like the tool <3 It will have a lot more content soon :)
geongeorgek on HNlove the idea! I would crowdsource it so people can add their regex and vote on other people rexgexes!
hamid_ra on HN
Questions
Is the IPv4 diagram repeat count correct
From 1 comment
Is there a bug? In regexp for IPv4: https://ihateregex.io/expr/ip expression ends with {3} but the diagram states "2 times" in lower right - shouldn't it say "3 times"?
dan_hawkins on HN
Diagram source credit to regexper missing in frame
From 1 comment
I don't understand why the Github repository lists regexper as the source of the visual graph code but the frame only shows iHateRegex as watermark? If the only thing that is…
KenanSulayman on HN
Alternatives named
regex101
From 2 comments
My go-to is https://regex101.com/
strig on HNNice tool! I personally use https://regex101.com/ as I like the explanations and quick reference.
xxsaculxx on HN
regexr
From 1 comment
Nobody pointed it out, but there's also https://regexr.com/ It's how I learned regex years ago, and I still use it today to test/build more complex patterns.
darau1 on HN
regexper
From 1 comment
Here is my goto resource for checking regexpr with railroad diagrams: https://regexper.com/
smartmic on HN
Patterns app
From 1 comment
if you're on osx, the app Patterns is really good for testing regex, and also has quick references for a variety of regex 'engines' and also has decent matching explanations…
waz0wski on HN