chinašØš³last time when did you use Regular Expressions?
Today, to configure fail2ban. Before that, yesterday to select which tests to run.
Usually I use glob patterns for test selection.
But I did use reges yesterday to find something else. A java security file definition.
We use it for triaging test failure (running tens of thousands of tests for CPU design verification).
That use is acceptable because it is purely informational. In general you should avoid regexes at all costs. Theyāre difficult to read, and easy to get wrong. Generally they are a very big red flag.
Unfortunately they tend to get used where they shouldnāt due to lazy developers not parsing things properly.
regexes are a well established solution for parsing strings. what exactly is the alternative you propose?
spartanatreyuThere are some tools/libraries that act as a front-layer over regex.
They basically follow the same logic as ORMs for databases:
But thereās no common standard, and itās always language specific.
Personally I think using linters is the best option since it will highlight the footguns and recommend simpler regexes. (e.g. Swapping [0-9] for \d)
At least once every few days while coding, usually to do one of the following:
Normally I use multicursor keyboard shortcuts to select what I want and for the trickier scenarios there are also commands to go through selections one at a time so you can skip certain matches to end up with only what you want.
But sometimes there are too many false matches that you donāt want to select by hand and thatās where regex comes in handy.
For instance, finding:
- parent but not apparent, transparent, parentheses, apparently, transparently
- test but not latest, fastest, testing, greatest, shortest
- trie but not entries, retries, countries, retrieve
- http but not https
ā¦ which can be easily done by searching for a word that doesnāt include a letter immediately before or immediately after: e.g. \Wtest\W.
Basically using the same things above
\d{4}, finding all versions: \d+\.\d+\.\d+, finding random things that a linter may have missed such as two empty lines touching each other: \n\s*\n\s*\n, etcā¦Yesterday. Gotta grep those logs.
KissakiEarlier this week for a character range.
Yesterday doing a search using vim for a class that shared a lot of characters at the front with many other classes: /Bas.*Some
I could have done a more precise search with better regex, but this was quick, easy, and worked.
Interesting to see a lot of these responses (so far) are workflow related instead of being used in production.
Probably, because in production there are really few things that are best done with regex. Most use I had for regex in production is filling in data from user-provided files with specifically crafted names, and even there there was some guesswork because of errors in naming, and the same thing may have been achieved without regex by splitting and/or iterating
Today.
THCDentonWriting the script that got me fired
I hope you are joking
Please explain more! What happened?
Did you destroy a database? Expose credentials? Nuke the company intentionally?
NostraDavidYesterday, when I had a file with a list of JSON objects, and I wanted to move the date field at the end to the beginning, so I used regex find and replace to move it. Something like \{(.*?), (ādateā: ā.*?ā) in Search, and then {$2, $1 in replace (or something close to it).
Yes, I refactor code and data using regex. I canāt be arsed to learn AWK (even though I should).
AWK doesnāt work with json IIRC. You have to use jq to deal with json.
While yes, the way I had it structured looked like a CSV if you squinted a little, I do fully agree AWK canāt be used for just any old JSON.
jq is dope, but that language still feels pretty confusing IMO.
Every day pretty much with Unix tools. Vim, awk, sed, etc.
Usually many times a dayā¦ Even today which have been mostly meetings.
Yesterday, for capturing URLs.
https?//[a-zA-Z0-9_-]*
I am kinda learning RE right now š
What about ftp? š¤
If we want to include every protocol then the RE could be complex.
Depending on the use-case it maybe should. On the other hand, some things are better left to library implementations rather than custom regex, e.g. email validation
I donāt always use regular expressions, but when I do, I use it to parse XML,
iirc using RE to parse tag languages is not recommended.
Sure, but if you are not regularly expressing code that has the potential of summoning elder gods that will swallow your soul into a dimension of ceaseless screaming then are you really living?
A few hours ago.
I just wanted to make a list of AD group names into a powershell array.
Asking this question is like asking when was the last time you had to search through text.
This sentence is the uncanny valley for structure.
On average Iāve probably had to work with them or write one from scratch only a handful of times per year over my career. Not often enough to be an expert or anything but Iām not so afraid of them as I used to be.
lacaio š§š·š“āā ļøšøš“I used it to check a user input format.