Question

Help me with this Python Question

a. build_word_dictionary (filename) – This builds a word dictionary indexed by words from the file who’s filename is provided as an argument. It uses the words as keys and the count of occurrences as values. It returns the dictionary it constructed. It can use the ‘tokenize()’ function that is provided in the lecture slides.

b. inverse_dict(dict) – This method takes a dictionary (generated by build_word_dictionary() and inverts it (as was done with students and majors in the lecture slides). The count of occurrences should now be the key. The values will be a list of words that occurred that many times. This method returns a list of lists.

c. dict_to_list(dict) – This method takes the dictionary and collects the keys from the dictionary into a list. It then sorts the list in alphabetical order using Python’s sort() method. It returns the sorted list

d. dict_to_list_by_count(dict) – This method takes the inverted list (where the number of occurrences is the key and the values are lists of words). It returns the list of lists in reverse order (most frequently occurring words to least frequently occurring).

Remember that in dict_to_list_by_count(), when building the final list, you can sort the counts that you added to a list but can use them to retrieve the values (word lists) from the original dictionary to build the final list of lists you will return.

Answer 1

# Here is the python code that reads from a file file.txt with comments and working screenshots

# you will have to work the indentation for yourself because HomeworkLib doesnt allow to add indentation but I can upload the file to ideone

# find it here https://ideone.com/3FSOxY

def build_word_dictionary (filename):
# this function reads from provided filename line by line (it wont take \n at the end)
  
word_dict = {} # this will store the word frequencies
with open(filename,'r') as f:
for line in f:
for word in line.split():
if word not in word_dict:
word_dict[word] = 1 # insert the word in the dict
else:
word_dict[word] += 1 # increase the count if already exists
  
return word_dict

def inverse_dict(dict):
# this function reverses the given dictionary
  
inv_dict = {}
for key,value in dict.items():
if value not in inv_dict:
inv_dict[value] = [key] # start a new list because this is the first occurence for given value
else:
inv_dict[value].append(key) # append to the already existing list for this value
  
return inv_dict

def dict_to_list(dict):
# converts keys of dictionaries to a sorted list
my_list = [key for key in dict.keys()] # create list from dict keys
return sorted(my_list) # return sorted list

def dict_to_list_by_count(dict):
# returns list of list from inverted dictionary in descending order of counts
list_of_lists = []
for key,values in sorted(dict.items())[::-1]: # this will iterate sorted dictionary in descending order
list_of_lists.append(values)
  
return list_of_lists

############## END OF FUNCTIONS

my_dict = build_word_dictionary('file.txt')
print("Output of Function 1: ", my_dict)
print()

inv_dict = inverse_dict(my_dict)
print("Output of Function 2: ", inv_dict)
print()

sorted_keys = dict_to_list(my_dict)
print("Output of Function 3: ", sorted_keys)
print()

list_of_lists = dict_to_list_by_count(inv_dict)
print("Output of Function 4: ", list_of_lists)