Problem Set 5(Word Histogram)

Word Histogram

Histogram is a graphical representation drawn based on the frequency of occurrence of things. Histogram for a word is drawn based on the number of occurrences of each character in the word. An inverted dictionary is used to maintain the list of characters that has same frequency. Write an algorithm and the subsequent Python code to compute and print the frequency of occurrence of character as a dictionary (ch:count). Make the entire process to be case insensitive. For example, if the input word is ‘parrot’, then the dictionary with characters and frequency of occurrence is

{'a': 1, 'o': 1, 'p': 1, 'r': 2, 't': 1}

and the inverted dictionary is

{1: ['a', 'o', 'p', 't'], 2: ['r']}

Print dictionary in sorted order by key. Sort the values of each key in the inverted dictionary.

[Hint: use pprint function for printing dictionary in sorted order.

Syntax for pprint is

pprint(dictionary name)

Include the line “from pprint import pprint” in the top of your program

Check for boundary conditions and print 'Invalid input' if conditions are not met.

Input Format:

First line contains the input word

Output Format:

Dictionary of characters in the word as keys and count as values in sorted order by key.

Inverted dictionary in sorted order by key.

Boundary Conditions:

Given word should only contain alphabets

Input:

the word

Processing:

from pprint import pprint

flag = True

letter = {}

inv_let = {}

temp_list = []

if word.isalpha() == False:

    flag = False

else:

    for i in word:

        letter.setdefault(i,0)

        letter[i] += 1

    for v in set(letter.values()):

        for k in letter.keys():

            if letter[k] == v:

                temp_list.append(k)

        temp_list.sort()

        inv_let[v] = temp_list

        temp_list = []

Output:

print the inverted sorted dictionary if the input is valid else print invalid input

Algorithm:

Step1. import the pprint function from the pprint module

Step2. Get the word from the user

Step3. Check if the word contains only alphabets if yes then proceed to step4 else assign flag as False.

Step4. Assign flag as True and initialize letter,inv_let as dictionaries and temp_list as an empty list.

Step5. Let i iterate through the word

Step5.1. Assign i as the key and 0 as the default value and add these to the letter dictionary

Step5.2 Increment the value by 1.

Step6. Let v iterate through the set of values in the letter dictionary

Step6.1 let k iterate through the keys in the letter dictionary

Step6.1.1 if the value obtained by accessing the key k in letter dictionary is v then append k in the temp_list

Step6.2 let v be the key of inv_let dictionary and temp_list be the value

Step6.3 reinitialize temp_list as an empty list

Step7. If flag is equal to True display inv_let in the sorted order else display invalid input.

Step8. End

Program:
from pprint import pprint
word = input()
word = word.lower()
if word.isalpha() == False:
    flag = False
else:
    flag = True
    letter = {}
    inv_let = {}
    temp_list = []
    for i in word:
        letter.setdefault(i,0)
        letter[i] += 1
    for v in set(letter.values()):
        for k in letter.keys():
            if letter[k] == v:
                temp_list.append(k)
        temp_list.sort()
        inv_let[v] = temp_list
        temp_list = []
if flag == True:
    pprint(letter)
    pprint(inv_let)
else:

    print('Invalid input')