Python - find occurrences of list of strings within string

Question

I have a large string and a list of search strings and want to build a boolean list indicating whether or not each of the search strings exists in the large string. What is the

Answer 1

An implementation using the Aho Corasick algorithm (https://pypi.python.org/pypi/pyahocorasick/), which uses a single pass through the string:

import ahocorasick
import numpy as np

def check_strings(search_list, input):
    A = ahocorasick.Automaton()
    for idx, s in enumerate(search_list):
        A.add_word(s, (idx, s))
    A.make_automaton()

    index_list = []
    for item in A.iter(input):
        index_list.append(item[1][0])

    output_list = np.array([0] * len(search_list))
    output_list[index_list] = 1
    return output_list.tolist()

search_strings = ["hello", "world", "goodbye"]
test_string = "hello world"
print(check_strings(search_strings, test_string))