Adding Items To List When They Already Exist And When Using For Loop

This is a pretty simple question about lists and for loop. Assuming I have the following 2d-list: [ ['c', 'a', 't', 'c', 'a', 't'] ['a', 'b', 'c', 'a', 't, 'l'] ['c', 'a', 't',

Solution 1:

The problem is you're not checking how many times that substring occurs in the string. You also need to account for overlapping matches:

import re

defsearch_for_words(word_list, matrix):
    results = []
    for word in word_list:
        for line in matrix:
            line_string = ''.join(line)
            # find all overlapping matches of word in line_string
            matches = re.findall(r'(?=(' + word + '))', line_string)
            results.extend(matches)
    return results

If we run this on your second matrix:

m = [['a', 'p', 'p', 'l', 'e'], 
     ['a', 'g', 'o', 'd', 'o'],
     ['n', 'n', 'e', 'r', 't'],
     ['g', 'a', 'T', 'A', 'C'],
     ['m', 'i', 'c', 's', 'r'],
     ['P', 'o', 'P', 'o', 'P']]

word_list = ['apple', 'god', 'dog', 'CAT', 'PoP', 'poeT']

print(search_for_words(word_list, m))

we see the following output:

['apple', 'god', 'PoP', 'PoP']

Solution 2:

The answer to your first question is pretty simple. Just build a string and check it each time. Lose the first letter of the string if the string is longer than the target word.

outer= [['c', 'a', 't', 'c', 'a', 't'],
         ['a', 'b', 'c', 'a', 't', 'l'],
         ['c', 'a', 't', 'w', 'x', 'y']]

forinnerinouter:
  word = ""
  target = "cat"
  t_len = len(target)
  for letter ininner:
    word += letter
    if len(word) > t_len:
      word = word[1:]
    if word in target:
      print(target)

For the answer to your second question, you're probably best to just "".join() all of the strings and parse them with regex.