...) The substring matched by the group is accessible by name.
(?P=name) Matches the text matched earlier by the group named name.
(?#...) A comment; ignored.
(?=...) Matches if ... matches next, but doesn't consume the string.
(?!...) Matches if ... doesn't match next.
(?<=...) Matches if preceded by ... (must be fixed length).
(?= 0x02020000:
__all__.append("finditer")
def finditer(pattern, string, flags=0):
"""Return an iterator over all non-overlapping matches in the
string. For each match, the iterator returns a match object.
Empty matches are included in the result."""
return _compile(pattern, flags).finditer(string)
def compile(pattern, flags=0):
"Compile a regular expression pattern, returning a pattern object."
return _compile(pattern, flags)
def purge():
"Clear the regular expression cache"
_cache.clear()
_cache_repl.clear()
def template(pattern, flags=0):
"Compile a template pattern, returning a pattern object"
return _compile(pattern, flags|T)
_alphanum = frozenset(
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
def escape(pattern):
"Escape all non-alphanumeric characters in pattern."
s = list(pattern)
alphanum = _alphanum
for i, c in enumerate(pattern):
if c not in alphanum:
if c == "\000":
s[i] = "\\000"
else:
s[i] = "\\" + c
return pattern[:0].join(s)
# --------------------------------------------------------------------
# internals
_cache = {}
_cache_repl = {}
_pattern_type = type(sre_compile.compile("", 0))
_MAXCACHE = 100
def _compile(*key):
# internal: compile pattern
cachekey = (type(key[0]),) + key
p = _cache.get(cachekey)
if p is not None:
return p
pattern, flags = key
if isinstance(pattern, _pattern_type):
if flags:
raise ValueError('Cannot process flags argument with a compiled pattern')
return pattern
if not sre_compile.isstring(pattern):
raise TypeError, "first argument must be string or compiled pattern"
try:
p = sre_compile.compile(pattern, flags)
except error, v:
raise error, v # invalid expression
if len(_cache) >= _MAXCACHE:
_cache.clear()
_cache[cachekey] = p
return p
def _compile_repl(*key):
# internal: compile replacement pattern
p = _cache_repl.get(key)
if p is not None:
return p
repl, pattern = key
try:
p = sre_parse.parse_template(repl, pattern)
except error, v:
raise error, v # invalid expression
if len(_cache_repl) >= _MAXCACHE:
_cache_repl.clear()
_cache_repl[key] = p
return p
def _expand(pattern, match, template):
# internal: match.expand implementation hook
template = sre_parse.parse_template(template, pattern)
return sre_parse.expand_template(template, match)
def _subx(pattern, template):
# internal: pattern.sub/subn implementation helper
template = _compile_repl(template, pattern)
if not template[0] and len(template[1]) == 1:
# literal replacement
return template[1][0]
def filter(match, template=template):
return sre_parse.expand_template(template, match)
return filter
# register myself for pickling
import copy_reg
def _pickle(p):
return _compile, (p.pattern, p.flags)
copy_reg.pickle(_pattern_type, _pickle, _compile)
# --------------------------------------------------------------------
# experimental stuff (see python-dev discussions for details)
class Scanner:
def __init__(self, lexicon, flags=0):
from sre_constants import BRANCH, SUBPATTERN
self.lexicon = lexicon
# combine phrases into a compound pattern
p = []
s = sre_parse.Pattern()
s.flags = flags
for phrase, action in lexicon:
p.append(sre_parse.SubPattern(s, [
(SUBPATTERN, (len(p)+1, sre_parse.parse(phrase, flags))),
]))
s.groups = len(p)+1
p = sre_parse.SubPattern(s, [(BRANCH, (None, p))])
self.scanner = sre_compile.compile(p)
def scan(self, string):
result = []
append = result.append
match = self.scanner.scanner(string).match
i = 0
while 1:
m = match()
if not m:
break
j = m.end()
if i == j:
break
action = self.lexicon[m.lastindex-1][1]
if hasattr(action, '__call__'):
self.match = m
action = action(self, m.group())
if action is not None:
append(action)
i = j
return result, string[i:]