import re
regex = re.compile(r"^([0-9]+)/([0-9]+)/([0-9a-zA-Z_-]+)/([0-9]+)/(thumbnail+)/([0-9a-zA-Z\-\_]+)(\.jpg)$", flags=re.MULTILINE)
test_str = ("1530778610/2018/Jul/05/thumbnail/lake-u_8610.jpg\n"
"1530778610/2018/Jul/05/thumbnail/lakeu_8610.jpg")
subst = "/upload/$2/$3/$4/$1_sm.jpg"
result = regex.sub(subst, test_str)
if result:
print(result)
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