python字典操作实例详解

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

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
def drawLine(t, x1, y1, x2, y2):
  t.penup()
  t.goto (x1, y1)
  t.pendown()
  t.goto (x2, y2)
 
# 在坐标(x,y)处写文字
def drawText(t, x, y, text):
  t.penup()
  t.goto (x, y)
  t.pendown()
  t.write(text)
 
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)
 
#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, y, x+5, y)
  drawLine(t, x+5, y, x+5, 0)
  drawLine(t, x+5, 0, x-5, 0)
   
#绘制多个柱体
def drawBar(t):
  for i in range(count):
    drawRectangle(t, i+1, data[i])  
################# Turtle End ####################
 
     
#对文本的每一行计算词频的函数
def processLine(line, wordCounts):
  #用空格替换标点符号
  line = replacePunctuations(line)
  #从每一行获取每个词
  words = line.split() 
  for word in words:
    if word in wordCounts:
      wordCounts[word] += 1
    else:
      wordCounts[word] = 1
 
#空格替换标点的函数
def replacePunctuations(line):
  for ch in line:
    if ch in "~@#$%^&*()_-+=<>?/,.:;{}[]|\'""":
      line = line.replace(ch, " ")
  return line
 
def main():
  #用户输入一个文件名
  filename = input("enter a filename:").strip()
  infile = open(filename, "r")
   
  #建立用于计算词频的空字典
  wordCounts = {}
  for line in infile:
    processLine(line.lower(), wordCounts)
     
  #从字典中获取数据对
  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])
     
  infile.close()
   
  #根据词频结果绘制柱状图
  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)
  turtle.done()
     
#调用main()函数
if __name__ == '__main__':
  main()