import matplotlib.pyplot as pltdecisionNode=dict(boxstyle="sawtooth",fc="11.8");leafNode=dict(boxstyle="round4",fc="0.8");arrow_args=dict(arrowstyle="<-");def plotNode(nodeTxt,centerPt,parentPt,nodeType):    createPlot.ax1.annotate(nodeTxt,xy=parentPt,xycoords='axes fraction',xytext=centerPt,textcoords='axes fraction',va="center",ha="center",bbox=nodeType,arrowprops=arrow_args);def createPlot():    fig=plt.figure(1,facecolor='white');    fig.clf();    createPlot.ax1=plt.subplot(111,frameon=False);    plotNode('a decision node',(0.5,0.1),(0.1,0.5),decisionNode);    plotNode('a leaf node',(0.8,0.1),(0.3,0.8),leafNode);    plt.show();def getNumLeafs(myTree):    numLeafs=0;    firstStr=myTree.keys()[0];    print firstStr;    secondDict=myTree[firstStr];    print secondDict;    for key in secondDict.keys():        print key;        print secondDict[key];        if type(secondDict[key]).__name__=='dict':            numLeafs+=getNumLeafs(secondDict[key]);        else:            numLeafs+=1;    return numLeafs;def getTreeDepth(myTree):    maxDepth=0;    firstStr=myTree.keys()[0];    secondDict=myTree[firstStr];    for key in secondDict.keys():        if type(secondDict[key]).__name__=='dict':            thisDepth=1+getTreeDepth(secondDict[key]);        else:            thisDepth=1;        if thisDepth >maxDepth:            maxDepth=thisDepth;    return maxDepth;def retrieveTree(i):    listOfTrees=[{
    'no surfacing':{0:'no',1:{
    'flippers':{0:'no',1:'yes'}}}},{
    'no surfacing':{0:'no',1:{
    'flippers':{0:{
    'head':{0:'no',1:'yes'}},1:'no'}}}}];    return listOfTrees[i];def plotMidText(cntrPt,parentPt,txtString): #计算父亲和孩子中间地方 放文本    xMid=(parentPt[0]-cntrPt[0])/2.0+cntrPt[0];    yMid=(parentPt[1]-cntrPt[1])/2.0+cntrPt[1];    createPlot.ax1.text(xMid,yMid,txtString);def plotTree(myTree,parentPt,nodeTxt):    numLeafs=getNumLeafs(myTree);    depth=getTreeDepth(myTree);    firstStr=myTree.keys()[0];    cntrPt=(plotTree.xOff+(1.0+float(numLeafs))/2.0/plotTree.totalW,plotTree.yOff);    plotMidText(cntrPt,parentPt,nodeTxt); #画中间    plotNode(firstStr,cntrPt,parentPt,decisionNode);#画这个点    secondDict=myTree[firstStr];    plotTree.yOff=plotTree.yOff-1.0/plotTree.totalD;    for key in secondDict.keys(): #不是叶子        if type(secondDict[key]).__name__=='dict':            plotTree(secondDict[key],cntrPt,str(key));        else:            plotTree.xOff=plotTree.xOff+1.0/plotTree.totalW; #是叶子            plotNode(secondDict[key],(plotTree.xOff,plot.yOff),cntrPt,leafNode);            plotMidText((plotTree.xOff,plotTree.yOff),cntrPt,str(key));    plotTree.yOff=plotTree.yOff+1.0/plotTree.totalD;def createPlot(inTree):    fig=plt.figure(1,facecolor='white');    fig.clf();    axprops=dict(xticks=[],yticks=[]);    createPlot.ax1=plt.subplot(111,frameon=False,**axprops);    plotTree.totalW=float(getNumLeafs(inTree));    plotTree.totalD=float(getTreeDepth(inTree));    plotTree.xOff=-0.5/plotTree.totalW; #个人感觉这边是有点神奇的    plotTree.yOff=1.0;    print plotTree.xOff,plotTree.yOff;    plotTree(inTree,(0.5,1.0),'');    plt.show();