Question

python

1

import matplotlib.pyplot as plt

2

import numpy as np

3

4

abscissa = np.arange(20)

5

plt.gca().set_prop_cycle(

’

color

’

, [

’

red

’

,

’

green

’

,

’

blue

’

,

’

black

’

])

6

7

class MyLine:

8

9

def __init__(self,

*

args,

**

options):

10

#TO DO: IMPLEMENT FUNCTION

11

pass

12

13

def draw(self):

14

plt.plot(abscissa,self.line(abscissa))

15

16

def get_line(self):

17

return "y = {0:.2f}x + {1:.2f}".format(self.slope, self.intercept)

18

19

def __str__(self):

20

return self.get_line()

21

22

def __mul__(self,other):

23

#TO DO:IMPLEMENT FUNCTION

24

pass

25

26

x1 = MyLine((0,0), (5,5),options = "2pts")

27

x1.draw()

28

x2 = MyLine((5,0),-1/4, options = "point-slope")

29

x2.draw()

30

x3 = MyLine("(-4/5)

*

x + 5", options = "lambda")

31

x3.draw()

32

x4 = MyLine("x + 2", options = "lambda")

33

x4.draw()

34

35

print("The intersection of {0} and {1} is {2}".format(x1,x2,x1

*

x2))

36

print("The intersection of {0} and {1} is {2}".format(x1,x3,x1

*

x3))

37

print("The intersection of {0} and {1} is {2}".format(x1,x4,x1

*

x4))

38

39

40

plt.legend([x1.get_line(), x2.get_line(), x3.get_line(),x4.get_line()],

←

↩

loc=

’

upper left

’

)

41

plt.show()

Problem 2: Lines In class we reviewed the equation of lines: (10) Ay We also discussed "variable and"variable, the former binding to a tuple of actual parameters and the latter allowing you to set switches. In this problem, you'll complete a Line class that not only draws the lines, but allows someone to describe the line by using two points, a point and slope, or simply the formula. For the formula, we assume the variable is always in r You'll overload the operator to find the intersection of two lines and display (x.y) when they intersection and 0 when they do not. You should assume, at a minimum the class has three instance variables (but with some choices, it might have more) 1. slope 2. intercept 3. line-A x: f(x) For example, the line y 1.3z-8 would have slope of 1.3, intercept of 8 and lineAx 1.3*x-8 (12) For this problem, you only need to implement the_init and overloaded *function. lineclass 1 import matplotlib.pyplot as plt 2 import numpy as np 3 4 abscissa np.arange(20) 5 plt.gca().set_prop_cycle( color, ['red, 'green 'blue' 'black']) 7 class MyLine def-init-(self, *args , **options): 10 #TODO: IMPLEMENT FUNCTION pass 12 13 14 15 16 def draw(self): plt.plot(abscissa,self.line(abscissa)) def get_line(self): return "y 0:.2fłx 1:.2f".format(self.slope, self.intercept) 18 19 20 21 def _str__(self): return self.get line() def _mul__(self,other): 23 #TODO: IMPLEMENT FUNCTION 24 25 26 x1MyLine( (0,0), (5,5),options"2pts" 27 x1.draw() 28 x2MyLine( (5,0),-1/4, options"point-slope") 29 x2.draw) 30 x3 MyLine("(-4/5)*X+5", options"lambda" 31 x3.draw) 32 x4 - MyLine("x + 2", optionslambda") 33 x4.draw( 34 35 print("The intersection of (o and 11 is (2)".format (x1,x2,x1*x2)) 36 print("The intersection of tO and (1 is (2)". format(x1,x3,x1*x3)) 37 print("The intersection of tO and 1 is (2)". format(x1,x4,x1*x4)) 38 39 40 plt.legend([x1.get line(), x2.get line), x3.getline),x4.get_line()], - pass loc- 'upper left') 41 plt.show) 一y·1.00x +0.00 _ y#-0.25x + 1.25 y--0.80x +5.00 20 15- y-1.00x+2.00 10 -10 0.0 2.5 5.0 7.5 10.012.5 15.0 17.5 Figure 1: Plot of 4 lines. Session Output The intersection of y 1.00x0.00 and y --0.25x 1.25 is: The intersection of y = 1.00x + 0.00 and y = -0.80x + 5.00 is: (2.778, 2.778) The intersection of y -1.00x+0.00 and y1.00x+2.00 is: C) Deliverables Programming Problem 2 Complete the two functions Put your code for this problem in a new module named lineclass.py

Answer 1

#SOLUTION :

#FUNCTION 1 (Constructor __init__)

def __init__(self, slope, intercept, *args, **options):

# get current axes if user has not specified them
if not 'axes' in options:
options.update({'axes':plt.gca()})
ax = options['axes']

# if unspecified, get the current line color from the axes
if not ('color' in options or 'c' in options):
options.update({'color':ax._get_lines.color_cycle.next()})

# init the line, add it to the axes
super(ABLine2D, self).__init__([], [], *args, **options)
self._slope = slope
self._intercept = intercept
ax.add_line(self)

# cache the renderer, draw the line for the first time
ax.figure.canvas.draw()
self.__mul__(None)

# connect to axis callbacks
self.axes.callbacks.connect('xlim_changed', self.__mul__)
self.axes.callbacks.connect('ylim_changed', self.__mul__)

#FUNCTION 2 (__mul__)

def __mul__(self, other):
""" called whenever axis x/y limits change """
x = np.array(self.axes.get_xbound())
y = (self._slope * x) + self._intercept
self.set_data(x, y)
self.axes.draw_artist(self)