学习例子：
例子1：画奥运五环图形
import turtle turtle.showturtle() turtle.width(10) turtle.penup() turtle.goto(-70,0) turtle.pendown() turtle.color("blue") turtle.circle(40) turtle.penup() turtle.goto(-10,0) turtle.pendown() turtle.color("black") turtle.circle(40) turtle.penup() turtle.goto(50,0) turtle.pendown() turtle.color("red") turtle.circle(40) turtle.penup() turtle.goto(-45,-60) turtle.pendown() turtle.color("yellow") turtle.circle(40) turtle.penup() turtle.goto(20,-60) turtle.pendown() turtle.color("green") turtle.circle(40)
例子2：定义多点坐标_绘出折线_并计算起始点和终点距离
import turtle import math x1,y1 = 0,73 x2,y2 = 40,-40 x3,y3 = 10,14 x4,y4 = -83,-34 x5,y5 = 0,0 turtle.width(5) turtle.goto(x1,y1) turtle.goto(x2,y2) turtle.goto(x3,y3) turtle.goto(x4,y4) turtle.goto(x5,y5) distance = math.sqrt((x2-x4)**2+(y2-y4)**2) turtle.write(distance)
例子3：列表的控制
- 将”to be or not to be”字符串倒序输出
- 将”sxtsxtsxtsxtsxt”字符串中所有的 s 输出
例子4：控制语句的编写
print("请输入一个学生的成绩:") score = int(input()) mark = "" if score < 60: mark = "不及格" elif score < 80: mark = "及格" elif score < 90: mark = "良好" else: mark = "优秀" print("该学会的成绩是:",score,"评价为:",mark) print("该学会的成绩是:{0},其评价为:{1}".format(score,mark)) print("该学会的成绩是:{grade},其评价为:{part}".format(grade = score,part = mark))
例子5：象限判断
print("请输入x的值：") x = int(input()) print("请输入y的值：") y = int(input()) point = "" if x>0 and y>0: point = "第一象限" elif x<0 and y>0: point = "第二象限" elif x<0 and y<0: point = "第三象限" else: point = "第四象限" print("x = {0},y = {1},位于的象限是{2}".format(x,y,point))
改善：
score = int(input(" " 请输入一个在 0 0-100 之间的数字：" ")) degree = "ABCDE" num = 0 f if score>100 r or score<0: score = int(input(" " 输入错误！请重新输入一个在 0 0-100 之间的数字：" ")) else: num = score//10 f if num<6:num=5 print(" " 分数是 {0}, 等级是 {1}".format(score,degree[9-num])
例子6：画同心圆
import turtle color = ["blue","white","red","pink","green","purple","yellow","brown"] i = turtle.Pen() i.speed(15) i.width(5) for c in range(100): i.penup() i.goto(0,-10*c) i.pendown() i.color(color[c%len(color)]) i.circle(0+10*c) turtle.done()
例子7：画棋盘18*18
import turtle pen = turtle.Pen() pen.speed(10) for row in range(18): pen.penup() pen.goto(0,170-row*10) pen.pendown() pen.goto(170,170-row*10) for column in range(18): pen.penup() pen.goto(column*10,170) pen.pendown() pen.goto(column*10,0) turtle.done()
例子8：局部变量和全局变量效率测试
import math import time def test01(): start = time.time() for i in range(100000000): math.sqrt(30) end = time.time() print("耗时{0}".format(end-start)) def test02(): b = math.sqrt start = time.time() for i in range(100000000): b(30) end = time.time() print("耗时{0}".format(end-start)) test01() test02()
例子9：浅拷贝与深拷贝
#测试浅拷贝和深拷贝 t import copy f def testCopy(): '''测试浅拷贝''' a = [10, 20, [5, 6]] b = copy.copy(a) print( "a", a) print( "b", b) b.append(30) b[2].append(7) print(" " 浅拷贝 ......") print( "a", a) print( "b", b) f def testDeepCopy(): '''测试深拷贝''' a = [10, 20, [5, 6]] b = copy.deepcopy(a) print( "a", a) print( "b", b) b.append(30) b[2].append(7) print(" " 深拷贝 ......") print( "a", a) print( "b", b) testCopy() print( "*************") testDeepCopy()
结果：
运行结果： a [10, 20, [5, 6]] b [10, 20, [5, 6]] 浅拷贝...... a [10, 20, [5, 6, 7]] b [10, 20, [5, 6, 7], 30] ************* a [10, 20, [5, 6]] b [10, 20, [5, 6]] 深拷贝...... a [10, 20, [5, 6]] b [10, 20, [5, 6, 7], 30]
原理图
- 浅拷贝
- 深拷贝
例子10：传递不可变对象包含的子对象是可变的情况
a = (10,20,[5,6]) print("a:",id(a)) def test(m): print("m:",id(m)) m[0] = 100 #会报错，因为元组是不可以改变的 print(m) test(a) print(a)
a = (10,20,[5,6]) print("a:",id(a)) def test(m): print("m:",id(m)) m[2][0] = 500 #不回报错 print(m) test(a) print(a)
原理图
例子11：lambda表达式和匿名函数（函数也是一个对象）
f = lambda a,b,c,d:a*b+c*d ff = [lambda Clichong:Clichong*2,lambda Text:Text*Text ] def p(a,b,c): return a*b*c hh = [p,p] qq = [ff,hh,f] print("qq[0][1](9):",qq[0][1](9),"qq[0][0](9)",qq[0][0](9)) print("qq[1][0]:",qq[1][0](2,3,4),"qq[1][0]:",qq[1][1](3,4,5)) print("qq[2]:",qq[2](1,2,3,4))
例子12：nonlocal和global关键字的测试
#测试nonlocal关键字的用法 def outer(): b = 10 def inner(): nonlocal b print("inner:",b) b = 20 inner() outer() #测试全局变量的用法 gl = 100 def outer1(): global gl gl = 1 print("gl:",gl) def inner1(): print("gl+100:",gl+100) inner1() print(gl) outer1()
作业练习：
练习1：定义一个函数实现反响输出一个整数。比如：输入 3245，输出 5432.
def mathmethod(a): print("翻转后的结果",end = ':') b = str(a)[::-1] print(b) p = int(input("输入一个数字：")) mathmethod(p)
练习2：编写一个函数，计算下面的数列
def mathfuncion(n): if n == 1: return 1/2 else: return n/(n+1)+mathfuncion(n-1) a = int(input("请输入一个数字:")) print(mathfuncion(a))
练习3：输入三角形三个顶点的坐标，若有效则计算三角形的面积；如坐标无效，则给出提示。
import math x = [0,0,0] y = [0,0,0] for i in range(3): x[i] = int(input("输入第{0}点的x坐标：".format(i+1))) y[i] = int(input("输入第{0}点的y坐标：".format(i+1))) print("三点坐标为:({0},{1})、({2},{3})、({4},{5})".format(x[0],y[0],x[1],y[1],x[2],y[2])) p1 = (x[0],y[0]) p2 = (x[1],y[1]) p3 = (x[2],y[2]) def getsquare(a,b,c): if (a[0] == b[0] == c[0]) or (a[1] == b[1] == c[1]): print("此三点不构成三角形") else: def getland(t1,t2): return math.sqrt((t1[0]-t2[0])**2+(t1[1]-t2[1])**2) l1 = getland(p1,p2) l2 = getland(p2,p3) l3 = getland(p1,p3) l = (l1+l2+l3)/2 sq = math.sqrt(l*(l-l1)*(l-l2)*(l-l3)) print("三边长分别为:{0}、{1}、{2}".format(l1,l2,l3)) print("面积为:{0}".format(sq)) getsquare(p1,p2,p3)
练习4：输入一个毫秒数，将该数字换算成小时数，分钟数、秒数。
import time start = int(time.time()) sec = int(start/1000) min = int(sec/60) hou = int(min/24) print("hour:{0}，minute:{1},second:{2}".format(hou,min,sec))
练习5：使用海龟绘图。输入多个点，将这些点都两两相连。
import turtle pen = turtle.Pen() for i in range(4): x1 = int(input("x1:")) y1 = int(input("y1:")) x2 = int(input("x2:")) y2 = int(input("y2:")) pen.penup() pen.goto(x1,y1) pen.pendown() pen.goto(x2,y2) turtle.done()
