import re
s = 'xyxxxyyyxyxxyy'
pattern = 'xy*' # 'x' followed by zero or more 'y'
for match in re.findall(pattern, s):
print('Found: {!r}'.format(match))
'''
run:
Found: 'xy'
Found: 'x'
Found: 'x'
Found: 'xyyy'
Found: 'xy'
Found: 'x'
Found: 'xyy'
'''