Python regex of multiple occurrences of a string of 1+ consecutive chars within a string

Question

I need to find starting and ending positions of variable length sequences of chars, consisting of same 1 letter inside a string. I saw this topic Finding multiple occurrences of a string within a string in Python, but I assume it's a bit off.

The following gives me nothing, while I expect to have 5 elements found.

import re
s = 'aaaaabaaaabaaabaaba'
pattern = '(a)\1+'
for el in re.finditer(pattern, s):
    print 'str found', el.start(), el.end()

Thanks in advance.

[It works well, just use a **raw string literal**](https://ideone.com/SxWJdh). And you can only expect 4 results. Else, replace the `+` with `*`. — Wiktor Stribiżew, Jul 18 '17 at 13:44

score -1 · Accepted Answer · answered Jul 18 '17 at 13:44

-1

Since it is a regex, the backslash should not be escaped at the string level, but should be interpreted by the regex.

You can use a raw string:

import re
s = 'aaaaabaaaabaaabaaba'
pattern = r'(a)\1+'   # raw string
for el in re.finditer(pattern, s):
    print 'str found', el.start(), el.end()

This generates:

str found 0 5
str found 6 10
str found 11 14
str found 15 17

answered Jul 18 '17 at 13:44

Willem Van Onsem

1 Answers1