python - Regex matching 5-digit substrings not enclosed with digits

Question

I want to extract 5 continuous digits from the string

code I have written.

re.findall(r"((D|^)*)ddddd((D|$)*)", s)

but it can not pass the string

"Helpdesk-Agenten (m/w) Kennziffer: 12966"

The expected result is:

12966

Example 2:

#input
"Helpdesk-Agenten (m/w) Kennziffer: 12966abc"
# expected
12966

Example 3:

#input
"Helpdesk-Agenten (m/w) Kennziffer: 12966345"
# expected
"" (because the length of continuous digits is longer than 5)

Answer 1

Your current regex (((D|^)*)ddddd((D|$)*)) used with re.findall won't return the digit chunks because they are not captured. More, the (D|^)* and (D|$)* parts are optional and that means they do not do what they are supposed to do, the regex will find 5 digit chunks inside longer digits chunks.

If you must find 5 digit chunk not enclosed with other digits, use

re.findall(r"(?<!d)d{5}(?!d)", s)

See the regex demo

Details:

• (?<!d) - no digit is allowed before the current location
• d{5} - 5 digits
• (?!d) - no digit allowed after the current location.