File handling 18: Files and dictionary, Histogram, character frequency

# Write a program that creates a dictionary
# of the frequency of all characters in a file.
# display five most frequently occuring characters

# Files, Dictionary and Command line arguments
# Histogram - Character frequency

import sys
import operator

fname = sys.argv[1]
fs = open(fname, "r")

Char_freq = {}

while(True):
    Line = fs.readline().strip().lower()
   
    if not Line:
        break
   
    for ch in Line:
        if (ch.isalpha()):
            if ch in Char_freq:
                Char_freq[ch] += 1
            else:
                Char_freq[ch] = 1
           
for ch in Char_freq:
    print(ch, Char_freq[ch])

List1 = sorted(Char_freq.items(), key=operator.itemgetter(1), reverse=True)

print("Five most frequently occuring characters :")
for k,v in List1[0:5]:
    print(k,v)

fs.close()

Histogram - String - Character frequency

# Histogram - Character frequency

import operator

string1 = "An algorithm is a step-by-step procedure to solve a given problem. It is a well-defined computational procedure that takes some values as input, manipulates them using a set of instructions and produces some values as output and terminates in a finite amount of time. An algorithm, when formally written in a programming language is called a program, or code. Derivation of an algorithm that solves the problem and conversion of the algorithm into code, together,  is known as Algorithmic Problem Solving."
string1 = string1.lower()

dict1 = {}
for idx in range(97, 123, 1):
    count = string1.count(chr(idx))
    if(count != 0):
        dict1[chr(idx)] = count

print("Histogram")
print(dict1)


List1 = sorted(dict1.items(), key=operator.itemgetter(1), reverse=True)
dict2 = dict(List1[:5])
print("Most frequent 5 characters")
print(dict2)