I need help with the compression code according to the simplified Huffman algorithm with a fixed code length
compression on the text loaded from the keyboard, then we write to the screen a simple console application under Windows
Please show what you have tried so far.
We are glad to help, but expect you to make a good effort as well.
If you've already written some code, show what you've got, and where there is an issue.
instead of taking text from the string constant, I want user to be able to type any text from the keyboard, I would like to also add decompression
string = 'TRykTrak'
# Creating tree nodes
class NodeTree(object):
def __init__(self, left=None, right=None):
self.left = left
self.right = right
def children(self):
return (self.left, self.right)
def nodes(self):
return (self.left, self.right)
def __str__(self):
return '%s_%s' % (self.left, self.right)
# Main function implementing huffman coding
def huffman_code_tree(node, left=True, binString=''):
if type(node) is str:
return {node: binString}
(l, r) = node.children()
d = dict()
d.update(huffman_code_tree(l, True, binString + '0'))
d.update(huffman_code_tree(r, False, binString + '1'))
return d
# Calculating frequency
freq = {}
for c in string:
if c in freq:
freq[c] += 1
else:
freq[c] = 1
freq = sorted(freq.items(), key=lambda x: x[1], reverse=True)
nodes = freq
while len(nodes) > 1:
(key1, c1) = nodes[-1]
(key2, c2) = nodes[-2]
nodes = nodes[:-2]
node = NodeTree(key1, key2)
nodes.append((node, c1 + c2))
nodes = sorted(nodes, key=lambda x: x[1], reverse=True)
huffmanCode = huffman_code_tree(nodes[0][0])
print(' Char | Huffman code ')
print('----------------------')
for (char, frequency) in freq:
print(' %-4r |%12s' % (char, huffmanCode[char]))