fill_completions(fd) returns a dictionary whose keys are tuples and the values a
ID: 3775157 • Letter: F
Question
fill_completions(fd) returns a dictionary whose keys are tuples and the values are sets. This function takes as an opened file pointer. It returns the completion dictionary as described below. o The keys are tuples of the form (n, l) for a non-negative integer n and a lowercase letter l. o The value associated with key(n, l)is the set of words in the file that contain the letter l at position n. For simplicity, all words are converted to lower case. For example, if the file contains the word “Python” then the sets returned by c_dict[0,“p”], c_dict[1,“y”], c_dict[2,“t”], c_dict[3,“h”], c_dict[4,“o”], and c_dict[5,“n”] all contain the word “python” (as well as other words).
o Words are stripped of punctuation. o “Words” containing non-alphabetic characters are ignored, as are words of length 1 (since there is no reason to complete the latter).
• find_completions(prefix, c_dict) returns a set of strings. This function takes a prefix of a word (possibly empty) and a completions dictionary of the form described above. It returns the set of words in the completions dictionary, if any, that complete the prefix. It the prefix cannot be completed to any vocabulary words, the function returns the empty set
Explanation / Answer
main.py
import string
def fill_completions(c_dict, fd):
for line in fd:
line = line.strip()
word_list = line.split()
for word in word_list:
word = word.lower()
word = word.strip(string.punctuation)
#this cuts the words in the lines down to just the letters
count = 0
if word.isalpha() == False:
break
if len(word) == 1:
break
#if there are non alphabetic characters, or the word is only 1 long, we
#don't care about it
while count < len(word):
if (count,word[count]) in c_dict:
c_dict[(count,word[count])].add(word)
else:
c_dict[(count,word[count])] = set()
c_dict[(count,word[count])].add(word)
#we add the word to the matching set in the dictionary depending on
#where each letter is located
count += 1
def find_completions(prefix, c_dict):
count = 0
set3 = c_dict[(count,prefix[count])]
while count < len(prefix):
set3 = set3&c_dict[(count,prefix[count])]
count += 1
#this takes the set that goes with each letter of the prefix and checks
#the intersection of that set with every other letter in the prefix
return set3
def main():
my_dict = {}
file_str = "ap_docs.txt"
f_obj = open(file_str)
fill_completions(my_dict, f_obj)
f_obj.close()
#this just fills the dictionary with the provided file
while True:
prefix = str(input("Give me a prefix to complete: (press '#' to quit) "))
if prefix == "#":
break
set3 = find_completions(prefix, my_dict)
if set3 != set():
print(set3)
else:
print("Prefix has no completions.")
#this repeatedly prompts the user for a prefix and prints the possible
#words. if none are found, it says so.
main()
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