[Tutor] string codes
Steven D'Aprano
steve at pearwood.info
Tue Nov 26 12:59:26 CET 2013
On Tue, Nov 26, 2013 at 10:01:14AM +0000, Alan Gauld wrote:
> >Is there a method to compare a substring, without building a substring
> >from the big one? Like startswith or endswith, but anywhere inside the
> >string?
> > test = s[1, -1] == "bcd" # no!, builds a substring
>
> I assume you mean test = s[1:-1] == "bcd"
>
> > test = s.sub_is(1, -1, "bcd") # yes! what I'm searching
>
> You can use startswith() (or endswith) by providing the optional
> start and end arguments:
>
> test = s.startswith("bcd", 1, -1)
That doesn't work, unfortunately:
py> s = "abcdZZZZZZZ"
py> s[1:-1] == "bcd"
False
py> s.startswith("bcd", 1, -1)
True
Oops.
You'd have to do both startswith() and endswith() tests, and even then
it doesn't work:
py> s = "abcdZZZZZZZZabcde"
py> s[1:-1] == "bcd"
False
py> s.startswith("bcd", 1, -1) and s.endswith("bcd", 1, -1)
True
--
Steven
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