python习题练习(六)
参考书籍:python程序设计
chapter8.
test
from graphics import *
def handlekey(k, win):
if k == "r":
win.setBackground("pink")
if k == "w":
win.setBackground("white")
if k == "g":
win.setBackground("lightgray")
if k == "b":
win.setBackground("lightblue")
def handleclick(pt, win):
#create an Entry for user to type in
entry = Entry(pt, 10)
entry.draw(win)
#Go modal: loop until user types key
while True:
key = win.getKey()
if key == "Return": break
#undraw the entry and draw text0
entry.undraw()
typed = entry.getText()
Text(pt, typed).draw(win)
#clear(ignore) any mouse click that occurered during text entry
win.checkMouse()
def main():
win = GraphWin('Click and Type', 500, 500)
#Event Loop: handle key press and mouse clicks until the user presses the "q" key.
while True:
key = win.checkKey()
if key == "q": #loop exit
break
if key:
handlekey(key, win)
pt = win.checkMouse()
if pt:
handleclick(pt, win)
win.close()
main()
4.
#This pro print the Syracuse sequence.
#input: an int number
#output: seq.
def main():
n = int(input("Enter an int num:"))
l = [n]
while n > 1:
#process
if n % 2 == 0: #
n = n / 2
else:
n = 3 * n + 1
l.append(int(n))
print(l)
main()
5.
#This pro check whether the num is a prime number.
#input: num > 2
#output : prime or not
def main():
n = int(input("Enter an int num (num > 2):"))
f = "is"
for i in range(2, n):
if n % i == 0:
f = "is not"
break
print("The num {} prime.".format(f))
main()
6.
#This pro list all prime nums le than n.
#input: num
#output: a list.
def isPrime(n):
#return True if n is a prime number, whether false.
f = True
for i in range(2, n):
if n % i == 0:
f = False
break
return f
def main():
n = int(input("Enter a number: "))
l = []
i = 3
while i <= n:
if isPrime(i): l.append(i)
i += 1
print(l)
if __name__ == "__main__":
main()
7.
#This pro finds two prime numbers with their add equal to the given even num.
#input: a even num
#output: two prime nums.
def isPrime(n):
#return True if n is a prime number, whether false.
f = True
for i in range(2, n):
if n % i == 0:
f = False
break
return f
def isEven(n):
#return true if n is a even number, whether false.
f = True
if n % 2 == 1:
f = False
return f
def allPrime(n):
#return a list, with all prime nums le than n.
l = []
i = 3
while i <= n:
if isPrime(i): l.append(i)
i += 1
return l
def main():
num = int(input("Enter an even number: "))
if not isEven(num):
print("Even number, please!")
return
#get all prime nums le than n in a list.
l = allPrime(num)
for i in l:
j = num - i
if isPrime(j):
ans = [i, j]
break
print(ans)
if __name__ == "__main__":
main()
8.
#calculates the gcd of two natural num.
#input: two natural num.
#output: gcd.
def main():
m, n = input("Enter two natural num: ").split(',')
m = int(m)
n = int(n)
#n is lager.
if m > n: m, n = n, m
while m:
n, m = m, n % m
print(n)
if __name__ == "__main__":
main()
13.
#This pro plots the regression line between points.
from graphics import *
def drawWin():
#draw a window
win = GraphWin("regression line", 500, 500)
win.setBackground("white")
win.setCoords(0, 0, 100, 100)
return win
def drawDone(win):
#draw the done label
rec = Rectangle(Point(3, 3), Point(13, 8))
rec.setWidth(2)
rec.setOutline('black')
rec.setFill('white')
rec.draw(win)
def drawText(win):
tex = Text(Point(8, 5.5), "Done")
tex.setTextColor('black')
tex.draw(win)
def drawPoint(p, win):
#draw the point on the window.
p.setFill('black')
p.draw(win)
def isDone(p):
#return ture if done, otherwise false.
##suppose know the boundary of done rectangle.
p_x = p.getX()
p_y = p.getY()
d = False
if 3 <= p_x <= 13 and 3 <= p_y <= 8:
d = True
return d
def SumIssue(p, sum_x, sum_y, sum_xx, sum_xy):
p_x = p.getX()
p_y = p.getY()
sum_x += p_x
sum_y += p_y
sum_xx += p_x * p_x
sum_xy += p_x * p_y
return sum_x, sum_y, sum_xx, sum_xy
def drawLine(sum_x, sum_y, sum_xx, sum_xy, count, win):
#calculate m
ave_x = sum_x / count
ave_y = sum_y / count
m = (sum_xy - count * ave_x * ave_y) / (sum_xx - count * ave_x * ave_x)
#(x0, y0) and (x1, y1)
x0 = 0
y0 = ave_y + m * (x0 - ave_x)
x1 = 100
y1 = ave_y + m * (x1 - ave_y)
#draw the line
line = Line(Point(x0, y0), Point(x1, y1))
line.setWidth(2)
line.draw(win)
def main():
#background
win = drawWin()
drawDone(win)
drawText(win)
#sum initial
sum_x, sum_y, sum_xx, sum_xy, count= 0, 0, 0, 0, 0
#loop
while True:
p = win.getMouse()
if isDone(p): break
#draw the point
drawPoint(p, win)
#sum
sum_x, sum_y, sum_xx, sum_xy = SumIssue(p, sum_x, sum_y, sum_xx, sum_xy)
#count
count += 1
#draw the redression line
drawLine(sum_x, sum_y, sum_xx, sum_xy, count, win)
#click to quit
win.getMouse()
win.close()
if __name__ == "__main__":
main()
14.
#This pro changes the rgb of a ppm pic.
from graphics import *
def drawWin():
#draw a window
win = GraphWin("regression line", 500, 500)
win.setBackground("white")
win.setCoords(0, 0, 100, 100)
return win
def main():
#draw win
win = drawWin()
#open pic
filename = input("Enter the pic's name: ")
pic = Image(Point(50, 50), filename)
pic.draw(win)
#pic's information
for i in range(pic.getHeight()):
for j in range(pic.getWidth()):
r, g, b = pic.getPixel(j, i)
brightness = int(round(0.299 * r + 0.587 * g + 0.114 * b))
pic.setPixel(j, i, color_rgb(brightness, brightness, brightness))
update(30)
print("done!")
newname = input("save as another name: ")
pic.save(newname)
#click to quit
win.getMouse()
win.close()
if __name__ == "__main__":
main()