python实现lz78算法
时间: 2023-09-29 15:10:12 浏览: 85
LZ78编码的python实现
您好,可以通过以下代码实现lz78算法的压缩和解压缩功能:
压缩:
```python
def lz78_compress(data):
dictionary = {}
compressed_data = []
index = 0
while index < len(data):
prefix = ""
symbol = data[index]
while prefix + symbol in dictionary and index < len(data)-1:
prefix += symbol
index += 1
symbol = data[index]
if prefix + symbol not in dictionary:
dictionary[prefix + symbol] = len(dictionary) + 1
compressed_data.append(dictionary[prefix + symbol])
index += 1
return compressed_data
```
解压缩:
```python
def lz78_decompress(data):
dictionary = {1: ""}
index = 0
decompressed_data = ""
while index < len(data):
if data[index] in dictionary:
decompressed_data += dictionary[data[index]]
if index < len(data)-1:
symbol = data[index+1]
if symbol in dictionary:
dictionary[len(dictionary)+1] = dictionary[data[index]] + dictionary[symbol][0]
else:
break
else:
symbol = dictionary[data[index]-1] + dictionary[data[index]-1][0]
decompressed_data += symbol
dictionary[len(dictionary)+1] = symbol
index += 1
return decompressed_data
```
注意:这里的实现只是示例代码,并没有考虑效率和其他细节问题。实际使用中需要进行优化和改进。
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