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Learn RegEx step by step, from zero to advanced

regexlearn.com

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Re: Learn RegEx step by step, from zero to advanced

#61

Post by kataklasm »

quacked wrote: post #52
beckman466 wrote: post #27

Earlier quoted context omitted.

> I always look at these intros/descriptions of Regex with a heavy heart. They describe what regex's are, but none of the info is going to make much sense to someone who doesn't already know why they would want to learn them. > Catch 22 of trying to explain what they are. any teachers, or people who explain/document things for a living, have some good tips or templates to avoid this?

Yeah. 1) Encourage whoever you're teaching to stop you immediately if they don't feel like they understand something you're saying, even if it's a single word that's throwing them off, and especially if they're not rock-solid about a simple concept they "should already know". Modern school teaches people that "returning to the basics" is a waste of time; but as Feynman says, you should return to the basics often, as…

Very valuable insight, thank you a lot!

Re: Learn RegEx step by step, from zero to advanced

#62

Post by agumonkey »

da_chicken wrote: post #25
brainwipe wrote: post #13

I learn regex just before I need it. Every. Time. After 25 years, it just doesn't stick.

I simply don't want to memorize 3 or more different versions of the syntax codes. Sometimes I'm using .Net. Sometimes I'm using Python. Sometimes I'm using whatever oddball engine the developer chose. I know how regex works. I can use forward and backward references. I can combine complex patterns. I can match, extract, replace, transform, etc. Sometimes I have even used nested patterns (though I'd probably need half…

That's one heavy pain point in emacs for instance. Even though it seems trivial to map char classes and syntax switch it's so utterly tiring. To the point where my first reaction is "cli unix tools share most of the syntax, it's so fluid... runs grep"

Re: Learn RegEx step by step, from zero to advanced

#63

Post by mjmsmith »

tyingq wrote: post #23
shoeffner wrote: post #11

Earlier quoted context omitted.

You need to press enter/return to advance.

Actually, it needs to be uppercase "OK". I typed "ok" also, and scratched my head for a while. I get it should be obvious, but my brain just didn't get it right away.

Really doesn't help that the capitalized "OK" in "Start by typing OK in the RegEx field" is in a smaller font.

Re: Learn RegEx step by step, from zero to advanced

#64

Post by [deleted] »

quacked wrote: post #52
beckman466 wrote: post #27

Earlier quoted context omitted.

> I always look at these intros/descriptions of Regex with a heavy heart. They describe what regex's are, but none of the info is going to make much sense to someone who doesn't already know why they would want to learn them. > Catch 22 of trying to explain what they are. any teachers, or people who explain/document things for a living, have some good tips or templates to avoid this?

Yeah. 1) Encourage whoever you're teaching to stop you immediately if they don't feel like they understand something you're saying, even if it's a single word that's throwing them off, and especially if they're not rock-solid about a simple concept they "should already know". Modern school teaches people that "returning to the basics" is a waste of time; but as Feynman says, you should return to the basics often, as…

[deleted]

Re: Learn RegEx step by step, from zero to advanced

#65

Post by crispyambulance »

dougmwne wrote: post #34
Zhyl wrote: post #8

>Regular Expressions, abbreviated as RegEx or RegExp, are a string of characters created within the framework of RegEx syntax rules. You can easily manage your data with RegEx, which uses commands like finding, matching, and editing. Regex can be used in programming languages such as Phyton, SQL, Javascript, R, Google Analytics, Google Data Studio, and throughout the coding process. Learn regex online with examples a…

I think regex is absolutely terrible garbage. It’s very powerful, I do appreciate not having to write complex conditional statements, and it’s great that it’s available is so many languages and applications. But it’s just a bad tool, terribly unreadable, easy to introduce bugs, with lots of trial and error. It has too much brevity and would be much better if it were longer but more human readable. I’m sure there are…

Regex is a great tool. Just use good taste and don't overdo it with regexes.

They're very effective at what they do as long as you don't make insane brainteasers that make people curse your name.

Re: Learn RegEx step by step, from zero to advanced

#66

Post by mycall »

dougmwne wrote: post #34
Zhyl wrote: post #8

>Regular Expressions, abbreviated as RegEx or RegExp, are a string of characters created within the framework of RegEx syntax rules. You can easily manage your data with RegEx, which uses commands like finding, matching, and editing. Regex can be used in programming languages such as Phyton, SQL, Javascript, R, Google Analytics, Google Data Studio, and throughout the coding process. Learn regex online with examples a…

I think regex is absolutely terrible garbage. It’s very powerful, I do appreciate not having to write complex conditional statements, and it’s great that it’s available is so many languages and applications. But it’s just a bad tool, terribly unreadable, easy to introduce bugs, with lots of trial and error. It has too much brevity and would be much better if it were longer but more human readable. I’m sure there are…

This is why I like tools such as RegExBuddy which breaks down the regex into a graphics. It does real-time match highlights of test text and emulates most Regex engines.

Re: Learn RegEx step by step, from zero to advanced

#67

Post by wruza »

tyingq wrote: post #42
dougmwne wrote: post #34

Earlier quoted context omitted.

I think regex is absolutely terrible garbage. It’s very powerful, I do appreciate not having to write complex conditional statements, and it’s great that it’s available is so many languages and applications. But it’s just a bad tool, terribly unreadable, easy to introduce bugs, with lots of trial and error. It has too much brevity and would be much better if it were longer but more human readable. I’m sure there are…

You can get a feel for what that would look like here: https://metacpan.org/release/CHROMATIC/Regexp-English-1.01/v... But then you're just memorizing things like 'start_of_line' instead of '^'. Perhaps easier to read, but no easier to write.

        -> start_of_line
        -> literal('Flippers')
        -> literal(':')
        -> optional
                -> whitespace_char
        -> end
        -> remember
                -> multiple
                        -> digit;
I literally can’t parse this as a whole. /^Flippers:\s?(\d+)/ is so much more obvious compared to that utter nonsense.

Re: Learn RegEx step by step, from zero to advanced

#68

Post by wruza »

umvi wrote: post #20
Zhyl wrote: post #8

>Regular Expressions, abbreviated as RegEx or RegExp, are a string of characters created within the framework of RegEx syntax rules. You can easily manage your data with RegEx, which uses commands like finding, matching, and editing. Regex can be used in programming languages such as Phyton, SQL, Javascript, R, Google Analytics, Google Data Studio, and throughout the coding process. Learn regex online with examples a…

Regex is powerful but I've found like 90% of the time I encounter one it would have been far simpler and more readable to use find + substring indexing or string splitting. Imo replacing several nested if statements with a single esoteric regex is not necessarily a win. It depends on if pattern matching is really the best tool for the job.

find + substring indexing

An endless source of off-by-one errors, not to mention buffer overflows, index out of bounds exceptions, accidental negative indexing.

Re: Learn RegEx step by step, from zero to advanced

#69

Post by anthony_romeo »

dougmwne wrote: post #34
Zhyl wrote: post #8

>Regular Expressions, abbreviated as RegEx or RegExp, are a string of characters created within the framework of RegEx syntax rules. You can easily manage your data with RegEx, which uses commands like finding, matching, and editing. Regex can be used in programming languages such as Phyton, SQL, Javascript, R, Google Analytics, Google Data Studio, and throughout the coding process. Learn regex online with examples a…

I think regex is absolutely terrible garbage. It’s very powerful, I do appreciate not having to write complex conditional statements, and it’s great that it’s available is so many languages and applications. But it’s just a bad tool, terribly unreadable, easy to introduce bugs, with lots of trial and error. It has too much brevity and would be much better if it were longer but more human readable. I’m sure there are…

I’d argue that regex is elegant and an incredibly useful to have in development… but it’s definitely definitely easy to have ‘too much of a good thing’ here.

Re: Learn RegEx step by step, from zero to advanced

#70

Post by kaycebasques »

Zhyl wrote: post #8

>Regular Expressions, abbreviated as RegEx or RegExp, are a string of characters created within the framework of RegEx syntax rules. You can easily manage your data with RegEx, which uses commands like finding, matching, and editing. Regex can be used in programming languages such as Phyton, SQL, Javascript, R, Google Analytics, Google Data Studio, and throughout the coding process. Learn regex online with examples a…

> They describe what regex's are, but none of the info is going to make much sense to someone who doesn't already know why they would want to learn them.

I frequently use the journalist's "5 Ws and H" framework as a checklist procedure for ensuring my technical communication covers fundamental questions/ideas:

* Who

* What

* Where

* Why

* When

* How

The slightly tricky thing is that you have to formulate a question for each W based on your domain. For example what is a fruitful "where" question for RegEx? Nonetheless the checklist makes me less likely to miss very key ideas, such as "why" one would use RegEx.

To make this idea more procedural maybe we could just formulate it as ungrammatical questions where you put the key topic after each W:

* Who RegEx?

* What RegEx?

* Where RegEx?

* Why RegEx?

* When RegEx?

* How RegEx?

And then just let your mind flesh them out into more complete questions...

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