CODEWITHSUNDEEP
pythonregexpython-3.x
Aditya
Aditya

Reputation: 109

python re.search gives returns None even though substring is present in the string

I am trying to extract the position of assignment operators and conditional operators(and|or). I am very new to regular expression so please bear with me if the approach is wrong. I would also appreciate it if someone can provide a regular expression for the above statement as an example.

Right now I am parsing the string and the parentheses through a bunch of python functions to get the index and I have been successful at that. I wanted to give it a try using regex to see if it simplifies the solution.

test = "((condition one = 14) or ((condition two = 10) and (condition three = null)))"
re.search("(and$)", test).start()
m = re.search("and", test)
m.group()

Expected result - Index of the start position of 'and'

Actual result - NoneType Object has no attribute start

Upvotes: 0

Views: 744

Answers (2)

ymochurad
ymochurad

Reputation: 999

You are looking for a regex like:

test = "((condition one = 14) or ((condition two = 10) and (condition three = null)))"
i = re.search("(and)|(or)", test).start()
print i

This prints out position of first and or or found:

22

Edit: To use finditer you will need to update above code a little:

test = "((condition one = 14) or ((condition two = 10) and (condition three = null)))"
pattern = re.compile(r"(and)|(or)")
for m in pattern.finditer(test):
    print(m.start())

outputs: 

22
47

Upvotes: 1

Florian Bernard
Florian Bernard

Reputation: 2569

You can simplify your regex, by just putting the word you are looking for.

import re
test = "((condition one = 14) or ((condition two = 10) and (condition three = null)))"
i = re.search("and", test).start()
print(test[i:])

and (condition three = null)))

Upvotes: 0

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