分享一些Python学习题目
实例061:杨辉三角
题目: 打印出杨辉三角形前十行。
程序分析: 无。
def generate(numRows):
r = [[1]]
for i in range(1,numRows):
r.append(list(map(lambda x,y:x+y, [0]+r[-1],r[-1]+[0])))
return r[:numRows]
a=generate(10)
for i in a:
print(i)
实例062:查找字符串
题目: 查找字符串。
程序分析: 无。
s1='aabbxuebixuebi'
s2='ab'
s3='xue'
print(s1.find(s2))
print(s1.find(s3))
实例063:画椭圆
题目: 画椭圆。
程序分析: 使用 tkinter。
if __name__ == '__main__':
from tkinter import *
x = 360
y = 160
top = y - 30
bottom = y - 30
canvas = Canvas(width = 400,height = 600,bg = 'white')
for i in range(20):
canvas.create_oval(250 - top,250 - bottom,250 + top,250 + bottom)
top -= 5
bottom += 5
canvas.pack()
mainloop()
实例064:画椭圆、矩形
题目: 利用ellipse 和 rectangle 画图。。
程序分析: 无。
if __name__ == '__main__':
from tkinter import *
canvas = Canvas(width = 400,height = 600,bg = 'white')
left = 20
right = 50
top = 50
num = 15
for i in range(num):
canvas.create_oval(250 - right,250 - left,250 + right,250 + left)
canvas.create_oval(250 - 20,250 - top,250 + 20,250 + top)
canvas.create_rectangle(20 - 2 * i,20 - 2 * i,10 * (i + 2),10 * ( i + 2))
right += 5
left += 5
top += 10
canvas.pack()
mainloop()
实例065:画组合图形
题目: 一个最优美的图案。
程序分析: 无。
import math
from tkinter import *
class PTS:
def __init__(self):
self.x = 0
self.y = 0
points = []
def LineToDemo():
screenx = 400
screeny = 400
canvas = Canvas(width = screenx,height = screeny,bg = 'white')
AspectRatio = 0.85
MAXPTS = 15
h = screeny
w = screenx
xcenter = w / 2
ycenter = h / 2
radius = (h - 30) / (AspectRatio * 2) - 20
step = 360 / MAXPTS
angle = 0.0
for i in range(MAXPTS):
rads = angle * math.pi / 180.0
p = PTS()
p.x = xcenter + int(math.cos(rads) * radius)
p.y = ycenter - int(math.sin(rads) * radius * AspectRatio)
angle += step
points.append(p)
canvas.create_oval(xcenter - radius,ycenter - radius,
xcenter + radius,ycenter + radius)
for i in range(MAXPTS):
for j in range(i,MAXPTS):
canvas.create_line(points[i].x,points[i].y,points[j].x,points[j].y)
canvas.pack()
mainloop()
if __name__ == '__main__':
LineToDemo()