Python 正则表达式 - 有时模式可以在字符串的末尾，有时可以在中间

Question

I have a requirement to return a match if a following sub text is found but no other alphanumeric character should be before or after the sub text.

For example: searching for text "OCI" in a filename:

import re

file_pattern = r".*([^a-zA-Z0-9]OCI[^a-zA-Z0-9]).*"
text = "rce oci "

m = re.match(file_pattern, text, re.IGNORECASE) 
if m is not None:
    print(m)
else:
    print("no match found")

The above code works as intended text = "rce oci " -> match found - note there is an extra white space after oci here text = "rceoci" -> no match found

But if text = "rce oci" it does not return the match - note there is no extra white space here.

How can I possibly fix this?

Thanks

Answer 1

You can use word boundary in your pattern and change re.match to re.search :

import re

file_pattern = r"\bOCI\b"
text = "rce oci"

m = re.search(file_pattern, text, re.IGNORECASE) 
if m is not None:
    print(m)
else:
    print("no match found")

Note re.match checks for complete match which is not the case here with the updated pattern.