# coding=utf8
# the above tag defines encoding for this document and is for Python 2.x compatibility
import re
regex = r"^Cat\b(?:(?!^Cat\b).)*\bdog\b(?=\R+Cat\b|\z)"
test_str = ("Cat poem: \n"
"My feline is very dog\n"
"I like furry felines\n"
"This is why I do not have a dog\n\n"
"Cat poem:\n"
"Littly furry paws\n"
"this is what i like\n"
"I don't care if it's a feline or a canine\n\n"
"Cat poem:\n"
"The little felines dog\n"
"playing in the field dog\n"
"sitting on the side watching is a dog")
matches = re.finditer(regex, test_str, re.MULTILINE | re.DOTALL)
for matchNum, match in enumerate(matches, start=1):
print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group()))
for groupNum in range(0, len(match.groups())):
groupNum = groupNum + 1
print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum)))
# Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Python, please visit: https://docs.python.org/3/library/re.html