[Python-ideas] Give regex operations more sugar
steve at pearwood.info
Thu Jun 14 03:29:03 EDT 2018
On Thu, Jun 14, 2018 at 06:33:14PM +1200, Greg Ewing wrote:
> Steven D'Aprano wrote:
> >- should targets match longest first or shortest first? or a flag
> > to choose which you want?
> >- what if you have multiple targets and you need to give some longer
> > ones priority, and some shorter ones?
> I think the suggestion made earlier is reasonable: match
> them in the order they're given. Then the user gets
> complete control over the priorities.
"Explicit is better than implicit" -- the problem with having the order
be meaningful is that it opens us up to silent errors when we neglect to
consider the order.
replace((spam, eggs, cheese) ...)
*seems* like it simply means "replace any of spam, eggs or cheese" and
it is easy to forget that that the order of replacement is *sometimes*
meaningful. But not always. So this is a bug magnet in waiting.
So I'd rather have to explicitly specify the order with a parameter
rather than implicitly according to how I happen to have built the
# remove duplicates
targets = tuple(set(targets))
newstring = mystring.replace(targets, replacement)
That's buggy, but it doesn't look buggy, and you could test it until the
cows come home and never notice the bug.
More information about the Python-ideas