[Tutor] a little help with the re odule

[Alan Gauld]

On 18/07/2020 11:57, nathan tech wrote:

> I'm trying to do a little bit of work with the re module but have rather 
> gotten stuck and am hoping someone will be able to fill in the gaps in 
> my understanding.

Sure, but first the usual caveat. regex are immensely powerful and quite
addictive. But very often the regular string methods are faster and
simpler. Don't let the cleverness of regex seduce you into over use.

That having been said...

> The match pattern is: The * sat on the *
> 
> Now with this example a bit of work with the \w match would work fine.

For single words yes. But you can combine regex with multipliers and
optional controls etc. regex is like a programming language with many
of the same control structures.

Also there will always be several ways to do it. It is worth bookmarking
one of the online regex testers to try out your regex to ensure it does
what you expect.

> What I can not figure out is lets say I have the match pattern: The * 
> sat on the *
> 
> What I want to do is for that to match all of the following:
> 
> the cat sat on the mat
> The dog sat on the shoe

While \w will work for a single word it gets more complex
with multiple words.

> The dog and the cat sat on the hoverboard.
> The big angry mouse sat on the mat and ate it.

This gets more complex because you want to match multiple words between
The and sat. The simplest way here is probably the .* combination
(zero or more repetitions of any character).

The .* sat on the .*

Or + if you want at least 1 character.

The .+ sat on the .+

But there are a myriad other ways to grab that content depending
on what exactly you plan on doing with the matches once you grab them.

You might find my tutorial topic on regex useful.

-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
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