CODEWITHSUNDEEP
pythonregexpython-re
Kamikaz Ali
Kamikaz Ali

Reputation: 23

How to match a string that a specific word doesn't comes before it?

I trying to match the string ARIBABA only if .get doesn't comes before it.

Example:

ARIBABA = config.get('SOMETHING', 'ARIBABA').lower()

I've tried this (down below) but it just doesn't match anything.

^(.get)\bARIBABA\b

Upvotes: 0

Views: 100

Answers (3)

Ryszard Czech
Ryszard Czech

Reputation: 18611

You must use PyPi regex library here:

import regex
s = "ARIBABA = config.get('SOMETHING', 'ARIBABA').lower()"
p = r"(?<!\.get\b.*)\bARIBABA\b"
print(regex.findall(p, s))

See Python proof.

EXPLANATION

--------------------------------------------------------------------------------
  (?<!                     look behind to see if there is not:
--------------------------------------------------------------------------------
    \.                       '.'
--------------------------------------------------------------------------------
    get                      'get'
--------------------------------------------------------------------------------
    \b                       the boundary between a word char (\w)
                             and something that is not a word char
--------------------------------------------------------------------------------
    .*                       any character except \n (0 or more times
                             (matching the most amount possible))
--------------------------------------------------------------------------------
  )                        end of look-behind
--------------------------------------------------------------------------------
  \b                       the boundary between a word char (\w) and
                           something that is not a word char
--------------------------------------------------------------------------------
  ARIBABA                  'ARIBABA'
--------------------------------------------------------------------------------
  \b                       the boundary between a word char (\w) and
                           something that is not a word char

Upvotes: -1

Mike
Mike

Reputation: 644

Here is pure regex solution.

pattern = "^(?!.*\.get).*(ARIBABA)"
aribaba = "config.get('SOMETHING', 'ARIBABA').lower()"
try:
    re.search(pattern, aribaba).group(1)
except:
    print("No ARIBABA or get comes before")

Upvotes: -1

Niv Dudovitch
Niv Dudovitch

Reputation: 1658

You can simply try this one:

if 0 =< s.find('.get') < s.find('ARIBABA'):

s.find(substring) returns the lowest index of s that begins with the substring

Full example:

s = "config.get('SOMETHING', 'ARIBABA').lower()"
if 0 =< s.find('.get') < s.find('ARIBABA'):
    print('.get comes before ARIBABA')

Output:

.get comes before ARIBABA

EDIT: if the substring doesn't exist in s, find will return -1, that's why I added the 0=< condition

Upvotes: 5

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