I was surprised to find that "this works": if you want to find all
_overlapping_ matches for a regexp R, wrap it in
(?=(R))
and feed it to (say) finditer. Here's a very simple example, finding
all overlapping occurrences of "xx":
pat = re.compile("(?=(xx))")
for it in pat.finditer("xxxx"):
print(it.span(1))
That displays:
(0, 2)
(1, 3)
(2, 4)
Is that a feature? Or an accident? It's very surprising to find a
non-empty match inside an empty match (the outermost lookahead
assertion). If it's intended behavior, it's just in time for the
holiday season; e.g., to generate ASCII art for half an upside-down
Christmas tree:
pat = re.compile("(?=(x+))")
for it in pat.finditer("xxxxxxxxxx"):
print(it.group(1))
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