Python实现的哈夫曼编码，python哈夫曼,#coding:utf-

Python实现的哈夫曼编码，python哈夫曼,#coding:utf-

#coding:utf-8import structcodeDict={}#全局字典key=字符，value=数字encodeDict={}filename=NonelistForEveryByte=[]class Node:    def __init__(self,right=None,left=None,parent=None,weight=0,charcode=None):        self.right=right        self.left=left        self.parent=parent        self.weight=weight        self.charcode=charcode#按权值排序def sort(list):    return sorted(list,key=lambda node:node.weight)#构建哈夫曼树def Huffman(listOfNode):    listOfNode=sort(listOfNode)    while len(listOfNode)!=1:        a,b = listOfNode[0],listOfNode[1]        new=Node()        new.weight, new.left, new.right = a.weight + b.weight, a, b        a.parent, b.parent = new, new        listOfNode.remove(a), listOfNode.remove(b)        listOfNode.append(new)        listOfNode=sort(listOfNode)    return listOfNodedef inPutFile():    global filename    global  listForEveryByte    filename=raw_input("请输入要压缩的文件：")    global  codeDict    with open(filename,'rb') as f:        data=f.read()        for Byte in data:            codeDict.setdefault(Byte,0) #每个字节出现的次数默认为0            codeDict[Byte]+=1            listForEveryByte.append(Byte)def outputCompressedFile():    global  listForEveryByte    fileString=""    with open(filename.split(".")[0]+".jbj","wb") as f:        for Byte in listForEveryByte:            fileString+=encodeDict[Byte]  #构成一个长字符序列        leng=len(fileString)        more=16-leng%16        fileString=fileString+"0"*more          #空位用0补齐        #print(fileString)        leng=len(fileString)        i,j=0,16        while j<=leng:            k=fileString[i:j]            a=int(k,2)            #print(a)           # print(repr(struct.pack(">H",a)))            f.write(struct.pack(">H",a))           # f.write(str(a))            i=i+16            j=j+16def encode(head,listOfNode):    global  encodeDict    for e in listOfNode:        ep=e        encodeDict.setdefault(e.charcode,"")        while ep!=head:            if ep.parent.left==ep:                encodeDict[e.charcode]="1"+encodeDict[e.charcode]            else:                encodeDict[e.charcode]="0"+encodeDict[e.charcode]            ep=ep.parentif __name__ == '__main__':    inPutFile()    listOfNode=[]    for e in codeDict.keys():        listOfNode.append(Node(weight=codeDict[e],charcode=e))    head=Huffman(listOfNode)[0]    #构建哈夫曼树，head称为树的根节点    encode(head,listOfNode)    for i in encodeDict.keys():         print(i,encodeDict[i])    #outputCompressedFile()