Finding multiple substrings in a string without iterating over it multiple times

Question

I need to find if items from a list appear in a string, and then add the items to a different list. This code works:

data =[]
line = \'akhgvfalfhda.dhgfa.lidh         


        

Answer 1

The following should work quite efficiently. It implements the suggestion from @SomeDude given above

lens=set([len(i) for i in _legal])
d={}
for k in lens:
    d[k]=[line[i:i+k] for i in range(len(line)-k)]
s=set(sum(d.values(), []))
result=list(s.intersection(set(_legal)))

for the following data (i changed "line" a bit as it returned an empty list due to uppecase in Thing1 and Thing2)

line = 'akhgvfalfhda.dhgfa.lidhfalihflaih**thing1**aoufgyafkugafkjhafkjhflahfklh**thing2**dlfkhalfhafli...'
_legal = ['thing1', 'thing2', 'thing3', 'thing4',...]

Output is:

print(result)

['thing2', 'thing1']

Explanation: We saved all possible lengths of the words in substrings. For these lengths, we created all possible substrings in text (set s). Finally we found common items in s and substrings, which is the answer to the question.