Fixing Python's string
The thing that has always irritated me about string
.join() is that it
doesn't stringify its arguments; if one of the things in the sequence to
be joined isn't a string,
.join() doesn't call
str() on it, it just
pukes. This is periodically annoying and inconvenient.
It recently occurred to me that this can be fixed, like so:
class StrifyingStr(str): def join(self, seq): s2 = [str(x) for x in seq] return super(StrifyingStr, self).join(s2) def str_join(js, seq): return StrifyingStr(js).join(seq)
(A similar version for Unicode strings is left as an exercise for the reader.)
You might think that a generator expression would be more efficient
than a list comprehension here; in fact, that's what my first version
used. Then I actually timed it, and found out that regardless of whether
.join() was passed a list or an iterator, and for sizes of
the list (or iterator) from 10 elements to 10,000, doing the list
comprehension was slightly faster.
Now that I have this I can think of a number of places where I may wind up using it, which kind of makes me wish I'd scratched this irritation before now.