python之字典类型

旧城等待， 2022-05-21 09:34 242阅读 0赞

字典基础

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字典操作

通过中括号可以增加字典的一项

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访问字典中的值，如果不存在则会报错

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删除命令

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遍历字典

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字典操作符

注意：字典不支持拼接操作符和重复操作符

从下图可以看出字典是无序的

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字典的方法

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字典示例1——统计词频

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步骤：

1.输入英文文章

2.建立用于词频计算的空字典

3.对文本的每一行进行计算词频

4.从字典中获取数据对到列表中

5.对列表中的数据对交换位置，并从大到小进行排序

6.输出结果

7.利用Turtle库绘制图表

#coding=gbk
    import turtle
    
    ##全局变量##
    #词频排列显示个数
    count = 10
    #单词频率数组-作为y轴数据
    data = []
    #单词数组-作为x轴数据
    words = []
    #y轴显示放大倍数-可以根据词频数量进行调节
    yScale = 6
    #x轴显示放大倍数-可以根据count数量进行调节
    xScale = 30
    
    
    #################Turtle start#####################
    #从点(x1,y1)到(x2,y2)绘制线段
    #在下面两个函数中，t是用于绘制的Turtle对象
    def drawLine(t,x1,y1,x2,y2):
        t.penup()
        t.goto(x1,y1)
        t.pendown()
        t.goto(x2,y2)
    
    def drawText(t,x,y,text):
        t.penup()
        t.goto(x,y)
        t.pendown()
        t.write(text)
    
    #绘制一个柱体
    def drawRectangle(t,x,y):
        x=x*xScale
        y=y*yScale#放大倍数显示
        drawLine(t,x-5,0,x-5,y)
        drawLine(t,x-5,0,x+5,y)
        drawLine(t,x+5,0,x+5,y)
        drawLine(t,x+5,0,x-5,y)
    
    #绘制多个柱体
    def drawBar(t):
        for i in range(count):
            drawRectangle(t, i+1, data[i])
    
    def drawGraph(t):
        #绘制x/y轴线
        drawLine(t, 0, 0, 360, 0)
        drawLine(t, 0, 300, 0, 0)
        
        #x轴：坐标及描述
        for x in range(count):
            x = x+1#向右移一位，为了不画在原点上
            drawText(t, x*xScale-4, -20, (words[x-1]))
            drawText(t, x*xScale-4, data[x-1]*yScale+10,data[x-1])
        drawBar(t)
        
    #空格替换标点的函数
    def replacePunctuation(line):
        for ch in line:
            if ch in "~@#$%^&()_-+=<>?/,.:;{}[]|\'""":
                line = line.replace(ch,"")
        return line
    
    
    #统计一行文本的词频
    def processLine(line,wordCounts):
        #用空格替换标点符号
        line=replacePunctuation(line)
        #从每一行获取没歌词
        words=line.split()
        for word in words:
            if word in wordCounts:
                wordCounts[word] += 1
            else:
                wordCounts[word] = 1
    
    def main():
        #strip()方法删除开头结尾的空格
        filename = input("enter a filename:").strip()
        infile = open(filename,"r")
        
        #建立用于计算词频的空字典
        wordCounts = {}
        #一个遍历文件内容的框架
        for line in infile:
            processLine(line.lower(), wordCounts)
        
        #下面是统计词频
        
        #获取字典数据对
        pairs = list(wordCounts.items())
        
        #列表中的数据对交换位置，数据对排序
        items = [[x,y]for (y,x) in pairs]
        items.sort()
        
        #输出count个数词频结果
        for i in range(len(items)-1,len(items)-count-1,-1):
            print(items[i][1]+"\t"+str(items[i][0]))
            data.append(items[i][0])
            words.append(items[i][1])
        
        turtle.title('词频结果柱状图')
        turtle.setup(900,750,0,0)
        t = turtle.Turtle()
        t.hideturtle()
        t.width(3)
        drawGraph(t)
        
    main()
    turtle.done()

运行结果如下：

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字典示例2——利用字典完成AddressBook的合并

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#coding=gbk
    
    def main():
        
        ftele2=open("TeleAddressBook.txt","rb")
        ftele1=open("EmailAddressBook.txt","rb")
        
        ftele1.readline()
        ftele2.readline()
        lines1=ftele1.readlines()
        lines2=ftele2.readlines()
        
        dic1 = {}
        dic2 = {}
        
        for line in lines1:#获取第一个文本中的姓名和电话信息
            elements=line.split()
            #将文本读出来的bytes转换为str类型
            dic1[elements[0]] = str(elements[1].decode('gbk'))
            
        for line in lines2:#获取第二个文本中的姓名和电话信息
            elements=line.split()
            #将文本读出来的bytes转换为str类型
            dic2[elements[0]] = str(elements[1].decode('gbk'))
            
        ###开始处理###
        lines = []
        lines.append('姓名\t    电话   \t  邮箱\n')
    
        for key in dic1:
            s= ''
            if key in dic2.keys():
                    s = '\t'.join([str(key.decode('gbk')), dic1[key], dic2[key]])
                    s += '\n'
            else:
                    s = '\t'.join([str(key.decode('gbk')), dic1[key], str('   -----   ')])
                    s += '\n'
            lines.append(s)
             
        for key in dic2:
            s= ''
            if key not in dic1.keys():
                    s = '\t'.join([str(key.decode('gbk')), str('   -----   '), dic2[key]])
                    s += '\n'       
            lines.append(s)
    
        ftele3 = open('AddressBook.txt', 'w')
        ftele3.writelines(lines)
    
        ftele3.close()
        ftele1.close()
        ftele2.close()
        print("The addressBooks are merged!")
    
    main()

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