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Use f-strings and remove unnecessary comments

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This commit is contained in:
Matthew Grove
2020-02-23 10:23:06 +00:00
parent 82d4b04fbc
commit 782bfe42f5
1 changed files with 13 additions and 25 deletions
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38
huffman-coding.py
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@@ -3,12 +3,10 @@ from collections import Counter
# function to find path of desired character # function to find path of desired character
def find_node(nodes, target_character): def find_node(nodes, target_character):
# for each item in nodes
for index, item in enumerate(nodes): for index, item in enumerate(nodes):
# if item is desired character, return the path to it
if item == target_character: if item == target_character:
# return its path
return [str(index)] return [str(index)]
# if the item is a list or tuple
if isinstance(item, (list, tuple)): if isinstance(item, (list, tuple)):
# run this function again to dig further into the nested items # run this function again to dig further into the nested items
path = find_node(item, target_character) path = find_node(item, target_character)
@@ -19,13 +17,13 @@ def find_node(nodes, target_character):
return [] return []
def encode(txt): def encode(txt):
# create list of tuples in descending order of frequency: (character, frequency) # list of tuples in descending order of frequency: (character, frequency)
info = Counter(txt).most_common() info = Counter(txt).most_common()
# change the list into ascending order # change the list into ascending order
info.reverse() info.reverse()
# create list for character tuples # list for character tuples
nodes = [] nodes = []
# create list for node usage frequencies # list for node usage frequencies
frequencies = [] frequencies = []
# copy nodes and their usage frequencies to the dedicated lists # copy nodes and their usage frequencies to the dedicated lists
@@ -44,40 +42,34 @@ def encode(txt):
# remove frequencies that have been summed and added to the new frequency # remove frequencies that have been summed and added to the new frequency
del frequencies[0:2] del frequencies[0:2]
# find index of last node with frequency below that of the new node # find index of the last node with a frequency below that of the new node
# if the largest frequency is smaller than the new one, place the new node at the end of the list # if the largest frequency is smaller than the new one, place the new node at the end of the list
if (frequencies[-1] < new_frequency): if (frequencies[-1] < new_frequency):
i = -1 i = -1
else: else:
# else, loop over every frequency # loop over every frequency
for index, item in enumerate(frequencies): for index, frequency in enumerate(frequencies):
# if the frequency is greater than or equal to the new frequency if (frequency >= new_frequency):
if (item >= new_frequency):
# record the index to insert the frequency at # record the index to insert the frequency at
i = index i = index
# stop looping
break break
# insert the new node in its rightful position, maintaining ascending order of frequency # insert the new node and frequency in their rightful positions, maintaining ascending order of frequency
nodes.insert(i, new_node) nodes.insert(i, new_node)
# insert the new frequency in its rightful position, maintaining ascending order of frequency
frequencies.insert(i, new_frequency) frequencies.insert(i, new_frequency)
# print all nodes print(f"Nodes: {nodes}")
print("Nodes: %s" % nodes)
# encrypted text # encrypted text
output = "" output = ""
# for every character in the text to be encrypted
for char in txt: for char in txt:
# find its path and add it to the encrypted text # find its path and add it to the encrypted text
output += "".join(find_node(nodes, char)) output += "".join(find_node(nodes, char))
# print encoded message print(f"Encoded message: {output}")
print("Encoded message: %s" % output)
# return encoded message
return [output, nodes] return [output, nodes]
def decode(txt, nodes): def decode(txt, nodes):
@@ -85,20 +77,16 @@ def decode(txt, nodes):
output = "" output = ""
# replicate nodes, for looping over and editing with the first part of the code # replicate nodes, for looping over and editing with the first part of the code
node = nodes node = nodes
# for each digit
for digit in txt: for digit in txt:
# get the node with the corresponding index # get the node with the corresponding index
node = node[int(digit)] node = node[int(digit)]
# if the retrieved node isn't a tuple (i.e. it isn't a parent node) # if the retrieved node isn't a tuple (i.e. it isn't a parent node)
if (not isinstance(node, tuple)): if (not isinstance(node, tuple)):
# add the node's content to the output
output += node output += node
# replace the retrieved node with the whole tree again, for looping over and editing with the next part of the code # replace the retrieved node with the whole tree again, for looping over and editing with the next part of the code
node = nodes node = nodes
# print decoded message print(f"Decoded message: {output}")
print("Decoded message: %s" % output)
# return decoded message
return output return output
encoding = encode(input("Text: ")) encoding = encode(input("Text: "))