CODEWITHSUNDEEP
pythonregexlist
C. Refsgaard
C. Refsgaard

Reputation: 227

Regex search list of strings in list of string

I have a list with words I wish to look for in another list:

listex = ['cat', 'mouse', 'dog']

And another list which is the one I wish to search through with the respective words in the list above:

listsearch = ['Hi there is a rabbit', 'how many dogs?', 'hot weather']

My thought is to use regex for each of the words in 'listex' on each of the strings in 'listsearch'. My goal is to get the index of the string in 'listsearch' that has been matched. For now, I have tried the following:

for search in listsearch:
  x = search
  if re.search(r"(?=("+'|'.join(listex)+r"))",x) is not None:
    a = re.search(r"(?=("+'|'.join(listex)+r"))",x)
    a=a.group(1)
    print(a)

dog

So what my current code gives me is the output "dog". But what I wish to get is the index that was matched in the "listsearch" - i.e. in the example above, I wish to get the index 1, as that is the index in "listsearch" that contains the word "dog"

Any ideas on how to get the index in the case?

Upvotes: 0

Views: 6583

Answers (2)

Inquisitor01
Inquisitor01

Reputation: 47

For a basic question, should "list comprehension" really be involved in the answer? I mean, I was thinking that someone might have wanted to have told him that regex wasn't necessary at all here, but if we want to use it maybe something a bit more basic could suffice.

import re

listex = ['cat', 'mouse', 'dog']
listsearch = ['Hi there is a rabbit', 'how many dogs?', 'hot weather']

for i in range(len(listex)):
    for ii in range(len(listsearch)):
            if re.findall(listex[i], listsearch[ii]):
                    print(str(ii)+': '+listex[i])

Output:

1: dog

Explanation:

  • I'm using i and ii purposely so you can more directly catch the index numbers of each array
  • I'm saying for each index/element of the listex array, iterate also through each element listsearch array, and use regex to find any occurrence of the individual term we are searching for in listex in the individual phrase we are searching through in listsearch
  • If that regex test is successful (aka if it returns something other than a blank array ([]), then print the index number in listsearch and print the term in listex which was found
  • Admittedly, not the most straightforward explanation, but play aroud with the code adding in something like 'I have a mouse' to the listsearch array and see the output

Upvotes: 0

DYZ
DYZ

Reputation: 57033

You can make your code much simpler:

results = [re.search('|'.join(listex),l) for l in listsearch]
#[None, <_sre.SRE_Match object; span=(9, 12), match='dog'>, None]
indexes = [i for i,v in enumerate(results) if v]
#[1]

Upvotes: 1

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