Re: Replacing substrings in a string

[Philippe Lhoste <PhiLho@...>]

David Given wrote:
> One thing I find myself needing to do suprisingly frequently is to replace all
> occurances of a particular substring with a different substring, in a larger
> string.
>
> Aha, you cry. string.gsub() is exactly what I'm looking for... except it's
> not, because I can't turn off regular expression processing, and my pattern is
> algorithmically generated and might contain '%' characters.
>
> What's the best way around this? What I'd *like* is for a 'plain' parameter to
> be added to string.gsub(), but of course that's unlikely to happen.

Although I believe it has been already asked...

> So far
> I've been using a fairly naive approach --- repeatedly calling string.find,
> constructing a list of fragments, and then concatenating them with
> table.concat. It's a bit verbose and quite irritating, and I'm not convinced
> about the speed. Are there any more cunning ways of doing this?

Perhaps that:

oldString = "Sale: 10% off, plus additional 5% off if 100% insured"
generatedPattern = "0%"
replace = "$"
pattern = string.gsub(generatedPattern, "%%", "%%%%")
newString = string.gsub(oldString, pattern, replace)
print(newString)

Seems to work, at least with this simplistic test...

--
Philippe Lhoste
--  (near) Paris -- France
--  http://Phi.Lho.free.fr
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