How to use positive lookbehind to find only certain 3 digit numbers?

Question

I have this text where I want to identify only certain three digit numbers using my depart city (NYC) as the positive lookbehind expression. I don't want to include it or anything else in the result, other than the desired three digit number.

I can't simply use \d{3,} because there are other three digit numbers in this text I haven't included here which should not be in the output.

Example string:

Depart: NYC (etd 9/30), NJ (etd 10/4)
Arrive LAX
Rate: USD500, 700P

My regular expression

(?<=NYC)(\D|\S)*\d{3,}

Output

 (etd 9/30), NJ (etd 10/4) Arrive LAX Rate: USD500, 700

However, I want it to output 700 only.

I've also tried

(?<=NYC)(?<=(\D|\S)*)\d{3,}

but this doesn't output anything.

Answer 1

You can use use

(?s)NYC.*?\b(\d{3,})

See the regex demo. Details:

• (?s) - re.DOTALL inline modifier
• NYC - NYC word
• .*? - any zero or more chars as few as possible
• \b - a word boundary
• (\d{3,}) - Group 1: three or more digits.

See the Python demo:

import re
text = """Depart: NYC (etd 9/30), NJ (etd 10/4)
Arrive LAX
Rate: USD500, 700P"""
m = re.search(r'(?s)NYC.*?\b(\d{3,})', text)
if m:
    print(m.group(1))

# => 700