How to properly apply OOP in the bouncing ball code
I'm trying to apply OOP in this bouncing ball code in order to have multiple
balls bouncing around the screen. The objective of this code is to create a
method called settings, which controls all the settings for the screen and the
bouncing behaviour of multiple balls, under the class Ball. However, I keep on
getting errors related to attributes (e.g., speed). I'm new to OOP in Python so
your help will be much appreciated. Thanks in advance.
import pygame
import random
import sys
pygame.init()
class Ball:
def __init__(self, X, Y):
self.velocity = [1,1]
self.ball_image = pygame.image.load ("ball.jpg")
self.ball_boundary = self.ball_image.get_rect ()
self.black = [0,0,0]
self.width = 800
self.height = 600
self.num = 8
self.X = random.randint(0, self.width)
self.Y = random.randint(0, self.height)
def settings(self):
#X = random.randint(0, self.width)
#Y = random.randint(0, self.height)
clock = pygame.time.Clock()
size = self.width, self.height
screen = pygame.display.set_mode(size)
ball_boundary = self.ball_image.get_rect()
speed = self.velocity
pic = self.ball_image
pygame.display.set_caption("Balls")
num_balls = self.num
ball_list = []
for i in range(num_balls):
ball_list.append( Ball(random.randint(10,
self.width-10),random.randint(10, self.height-10)) )
while 1:
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit(0)
screen.fill(self.black)
for balls in ball_list:
if balls.ball_boundary.left < 0 or balls.ball_boundary.right >
self.width:
balls.speed[0] = -balls.speed[0]
if balls.ball_boundary.top < 0 or balls.ball_boundary.bottom >
self.height:
balls.speed[1] = -balls.speed[1]
balls.ball_boundary = balls.ball_boundary.move (self.velocity)
screen.blit (balls.ball_image, balls.ball_boundary)
pygame.display.flip()
play = Ball(random.randint(0, 800), random.randint(0, 600))
play.settings()
Message File Name LinePosition
Traceback
C:\\Multiple_balls_TC.py63
settingsC:\\Multiple_balls_TC.py56
AttributeError: Ball instance has no attribute 'speed'
--
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Re: How to properly apply OOP in the bouncing ball code
Thanks for your help.
I have updated the code as follows, there are no more errors but the images
will not move at all, as all the images are staying at the upper left corner.
Please advice, thanks.
import sys, pygame
pygame.init()
size = width, height = 800, 600
black = [0,0,0]
screen = pygame.display.set_mode(size)
class BALL:
def __init__(self,image):
self.ball = pygame.image.load(image)
self.ballrect = self.ball.get_rect()
self.speed= [2, 2]
def control(self):
ballmove = self.ballrect.move(self.speed)
if ballmove.left < 0 or ballmove.right > width:
self.speed[0] = -self.speed[0]
if ballmove.top < 0 or ballmove.bottom > height:
self.speed[1] = -self.speed[1]
def settings(self):
clock = pygame.time.Clock()
screen.fill(black)
screen.blit(self.ball, self.ballrect)
pygame.display.flip()
clock.tick(60)
while 1:
for event in pygame.event.get():
if event.type == pygame.QUIT: sys.exit()
bob = BALL("spongebob.png")
bob.control()
bob.settings()
patrick = BALL("patrick.jpg")
patrick.speed[0] = 5
patrick.speed[1] = 8
patrick.control()
patrick.settings()
jaws = BALL("jaws.jpg")
jaws.speed[0] = 1
jaws.speed[1] = 10
jaws.control()
jaws.settings()
On Friday, May 8, 2015 at 11:40:46 AM UTC-4, Tommy C wrote:
> I'm trying to apply OOP in this bouncing ball code in order to have multiple
> balls bouncing around the screen. The objective of this code is to create a
> method called settings, which controls all the settings for the screen and
> the bouncing behaviour of multiple balls, under the class Ball. However, I
> keep on getting errors related to attributes (e.g., speed). I'm new to OOP in
> Python so your help will be much appreciated. Thanks in advance.
>
>
> import pygame
> import random
> import sys
>
> pygame.init()
>
> class Ball:
> def __init__(self, X, Y):
> self.velocity = [1,1]
> self.ball_image = pygame.image.load ("ball.jpg")
> self.ball_boundary = self.ball_image.get_rect ()
> self.black = [0,0,0]
> self.width = 800
> self.height = 600
> self.num = 8
> self.X = random.randint(0, self.width)
> self.Y = random.randint(0, self.height)
>
> def settings(self):
> #X = random.randint(0, self.width)
> #Y = random.randint(0, self.height)
> clock = pygame.time.Clock()
> size = self.width, self.height
> screen = pygame.display.set_mode(size)
> ball_boundary = self.ball_image.get_rect()
> speed = self.velocity
> pic = self.ball_image
> pygame.display.set_caption("Balls")
> num_balls = self.num
> ball_list = []
>
> for i in range(num_balls):
>ball_list.append( Ball(random.randint(10,
> self.width-10),random.randint(10, self.height-10)) )
>
> while 1:
> for event in pygame.event.get():
> if event.type == pygame.QUIT:
> sys.exit(0)
>
> screen.fill(self.black)
> for balls in ball_list:
> if balls.ball_boundary.left < 0 or balls.ball_boundary.right
> > self.width:
> balls.speed[0] = -balls.speed[0]
> if balls.ball_boundary.top < 0 or balls.ball_boundary.bottom
> > self.height:
> balls.speed[1] = -balls.speed[1]
> balls.ball_boundary = balls.ball_boundary.move (self.velocity)
> screen.blit (balls.ball_image, balls.ball_boundary)
> pygame.display.flip()
>
> play = Ball(random.randint(0, 800), random.randint(0, 600))
>
> play.settings()
>
>
>
>
> Message File Name LinePosition
> Traceback
> C:\\Multiple_balls_TC.py63
> settings C:\\Multiple_balls_TC.py56
> AttributeError: Ball instance has no attribute 'speed'
--
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Questions on Pandas
Hi there, I have a number of questions related to the Pandas exercises found
from the book, Python for Data Analysis by Wes McKinney. Particularly, these
exercises are from Chapter 6 of the book. It'd be much appreciated if you could
answer the following questions!
1.
[code]
Input: pd.read_csv('ch06/ex2.csv', header=None)
Output:
X.1 X.2 X.3 X.4 X.5
0 1 2 3 4 hello
1 5 6 7 8 world
2 9 10 11 12 foo
[/code]
Does the header appear as "X.#" by default when it is set to be None?
2.
[code]
Input: chunker = pd.read_csv('ch06/ex6.csv', chunksize=1000)
Input: chunker
Output:
[/code]
Please explain the idea of chunksize and the output meaning.
3.
[code]
The TextParser object returned by read_csv allows you to iterate over the parts
of the
file according to the chunksize. For example, we can iterate over ex6.csv,
aggregating
the value counts in the 'key' column like so:
chunker = pd.read_csv('ch06/ex6.csv', chunksize=1000)
tot = Series([])
for piece in chunker:
tot = tot.add(piece['key'].value_counts(), fill_value=0)
tot = tot.order(ascending=False)
We have then:
In [877]: tot[:10]
Out[877]:
E 368
X 364
L 346
O 343
Q 340
M 338
J 337
F 335
K 334
H 330
[/code]
I couldn't run the Series function successfully... is there something missing
in this code?
4.
[code]
Data can also be exported to delimited format. Let's consider one of the CSV
files read
above:
In [878]: data = pd.read_csv('ch06/ex5.csv')
In [879]: data
Out[879]:
something a b c d message
0 one 1 2 3 4 NaN
1 two 5 6 NaN 8 world
2 three 9 10 11 12 foo
Missing values appear as empty strings in the output. You might want to denote
them
by some other sentinel value:
In [883]: data.to_csv(sys.stdout, na_rep='NULL')
,something,a,b,c,d,message
0,one,1,2,3.0,4,NULL
1,two,5,6,NULL,8,world
2,three,9,10,11.0,12,foo
[/code]
Error occured as I tried to run this code with sys.stdout.
5.
[code]
class of csv.Dialect:
class my_dialect(csv.Dialect):
lineterminator = '\n'
delimiter = ';'
quotechar = '"'
reader = csv.reader(f, dialect=my_dialect)
[/code]
An error occurred when I tried to run this code: "quotechar must be an
1-character integer... please explain.
6.
[code]
with open('mydata.csv', 'w') as f:
writer = csv.writer(f, dialect=my_dialect)
writer.writerow(('one', 'two', 'three'))
writer.writerow(('1', '2', '3'))
writer.writerow(('4', '5', '6'))
writer.writerow(('7', '8', '9'))
[/code]
An error occurred when I ran this code. Please explain the cause of the error.
7.
[code]
But these are objects representing HTML elements; to get the URL and link text
you
have to use each element's get method (for the URL) and text_content method (for
the display text):
In [908]: lnk = links[28]
In [909]: lnk
Out[909]:
In [910]: lnk.get('href')
Out[910]: 'http://biz.yahoo.com/special.html'
In [911]: lnk.text_content()
Out[911]: 'Special Editions'
Thus, getting a list of all URLs in the document is a matter of writing this
list comprehension:
In [912]: urls = [lnk.get('href') for lnk in doc.findall('.//a')]
In [913]: urls[-10:]
Out[913]:
['http://info.yahoo.com/privacy/us/yahoo/finance/details.html',
'http://info.yahoo.com/relevantads/',
'http://docs.yahoo.com/info/terms/',
'http://docs.yahoo.com/info/copyright/copyright.html',
'http://help.yahoo.com/l/us/yahoo/finance/forms_index.html',
'http://help.yahoo.com/l/us/yahoo/finance/quotes/fitadelay.html',
'http://help.yahoo.com/l/us/yahoo/finance/quotes/fitadelay.html',
[/code]
An error related to line 912 occurred as I tried to run the code. Please
explain.
8.
[code]
Using lxml.objectify, we parse the file and get a reference to the root node of
the XML
file with getroot:
from lxml import objectify
path = 'Performance_MNR.xml'
parsed = objectify.parse(open(path))
root = parsed.getroot()
[/code]
An error occured when I tried to run the code to access the XML file. Please
explain.
9.
[code]
ML data can get much more complicated than this example. Each tag can have
metadata,
too. Consider an HTML link tag which is also valid XML:
from StringIO import StringIO
tag = 'http://www.google.com";>Google'
root = objectify.parse(StringIO(tag)).getroot()
You can now access any of the fields (like href) in the tag or the link text:
In [930]: root
Out[930]:
In [931]: root.get('href')
Out[931]: 'http://www.google.com'
In [932]: root.text
Out[932]: 'Google'
[/code]
The outputs for line 930 and 931 are the same as line 932 (i.e., Google).
Please explain
10.
[code]
One of the easiest ways to store data efficiently in binary format is using
Python's builtin
pickle serialization. Conveniently, pandas objects all have a save method which
writes the data to disk as a pickle:
In [933]: frame = pd.read_csv('ch06/ex1.csv')
In [934]: frame
Out[934]:
a b c d message
0 1 2 3 4 hello
1 5 6 7 8 world
2 9 10 11 12 foo
In [935]: frame.save('ch06/frame_pickle')
You read the data back into Python with pandas.load, another pickle convenience
function:
In [936]: pd.load('ch06/frame_pickle')
Out[936]:
a b c
