Multiple Occurrences of a Pattern in Python

Question

I'm new to python and I'm trying to construct a list of tuples with the start and end indices for pattern matching in a string.

I need to match a pattern that starts with 2 consecutive 0s and ends with 2 consecutive 1s with some combo of 0s and 1s in between.

For example,

s = '00101010111111100001011'

With some type of operation returning,

[(0, 10), (15, 23)]

I can find multiple occurrences of a pattern in a string using,

ind = [(m.start(), m.end()) for m in re.finditer(pattern, s)]

I'm just not sure how to write the regular expression (i.e pattern) to output what I want.

Wiktor Stribiżew · Accepted Answer · 2017-05-07 19:16:06Z

6

Use the following pattern:

00[01]*?11

Details:

00 - two consecutive 0s
[01]*? - zero or more 0 or 1 chars, as few as possible (as *? is a lazy quantifier)
11 - two consecutive 1 chars.

import re
s = '00101010111111100001011'
rx = r'00[01]*?11'
print([(x.start(),x.end()) for x in re.finditer(rx, s)])
# => [(0, 10), (15, 23)]

answered May 7, 2017 at 19:16

Wiktor Stribiżew

631k41 gold badges502 silver badges633 bronze badges

Sign up to request clarification or add additional context in comments.

1 Answer 1