条件、循环 、函数练习

1. 注意标准库的两种导入与使用方式，建议大家采用<库名>.<函数名>的方式。
2. 对前面的代码进行优化，用for,while,if,def实现：
   1. 用循环画五角星

      import turtle
      turtle.color("yellow")
      turtle.fillcolor("yellow")
      turtle.speed(8)
      turtle.begin_fill()
      for i in range(5):
        turtle.forward(200)
        turtle.right(144)
      turtle.end_fill()

   2. 用循环画同心圆

      from turtle import*
      for i in range(4):
          up()
          goto(0,-20*(i))
          down()
          circle(20*i)

   3. 用while循环画太阳花

      from turtle import*
      
      color('red','yellow')
      begin_fill()
      while True:
          forward(200)
          left(170)
          if (abs(pos()))<1:
              break
      end_fill()
      done()

   4. 用函数定义画五个五角星

      import turtle
      turtle.setup(600,400,0,0)
      turtle.color("yellow")
      turtle.bgcolor("red")
      turtle.fillcolor("yellow")
      turtle.speed(5)
      def goto(x,y):
        turtle.up()
        turtle.goto(x,y)
        turtle.down()
      def bigstar(z):
        turtle.begin_fill()
        for i in range(5):
            turtle.forward(z)
            turtle.right(144)
        turtle.end_fill() 
      goto(-250,125)
      bigstar(125)
      goto(-105,165)
      turtle.left(40)
      turtle.begin_fill()
      for i in range(5):
          turtle.forward(35)
          turtle.right(144)
      turtle.end_fill() 
      goto(-30,135)
      turtle.right(10)
      turtle.begin_fill()
      for i in range(5):
          turtle.right(144)
          turtle.forward(35)
      turtle.end_fill()
      goto(-40,75)
      turtle.left(40)
      turtle.begin_fill()
      for i in range(5):
          turtle.right(144)
          turtle.forward(35)
      turtle.end_fill()
      goto(-75,20)
      turtle.right(20)
      turtle.begin_fill()
      for i in range(5):
          turtle.right(144)
          turtle.forward(35)
      turtle.end_fill()

   5. 用函数定义画钻石花瓣的太阳花

      import turtle
      
      def draw_diamond(brad):
          brad.forward(100)
          brad.right(45)
          brad.forward(100)
          brad.right(135)
      
      def draw_art():
          
          window=turtle.Screen()
          brad=turtle.Turtle()
          brad.color("red")
          brad.speed("fastest")
      
      
          for i in range(0,36):
              draw_diamond(brad)
              draw_diamond(brad)
              brad.left(10)
      
          brad.right(90)
          brad.forward(155)
          brad.color('green')
          brad.forward(145)
      
          window.exitonclick()
      
      draw_art()

3. 字符串操作
   1. 输入学号，识别年级、专业、序号。

      num=input("输入学号:")
      print("你的年级是{}级".format(num[0:4]))
      if(int(num[8:10]))==43
          print("你的班级是网络工程一班")
      else print("你的班级未识别！")
      print("你在班级的序号是{}".format(num[-2:]))

   2. 输入1-7的数字，输出对应的“星期几”。

      s='星期一星期二星期三星期四星期五星期六星期日'
      a=int(input("输入数字（1-7）："))
      if(7>a>1)
          print(s[-3+3*a:0+3*a])
      else 
          print("输入错误！")

   3. 识别身份证号中的省市区、年龄、性别。

      num=input('请输入十八位身份证号码: ')
      if len(num)==18:
        print("你的身份证号码是 "+num)
      else:
        print("错误的身份证号码")
      num_add=ID[0:6]
      num_birth=ID[6:10]
      num_sex=ID[14:17]
      
      if int(num_add)==440101:
        print("省市区:广东省广州市市辖区")
      elif int(num_add)==440102:
          print("省市区:广东省广州市东山区")
      elif int(num_add)==440103:
          print("省市区:广东省广州市荔湾区")
      elif int(num_add)==440104:
          print("省市区:广东省广州市越秀区")
      elif int(num_add)==440105:
          print("省市区:广东省广州市海珠区")
      elif int(num_add)==440106:
          print("省市区:广东省广州市天河区")
      
          
      birth=2017-int(ID_birth[0:4])
      print("年龄：{}".format(birth)) 
        
      if int(ID_sex)%2==0:
        print('性别：女')
      else:
        print('性别：男')