[Tutor] Naming conventions
Hello Friends, Can you please suggest good naming conventions/guidelines to following while writing Python code? Thanks. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] Trouble Downloading 3.2 tutorial
Greetings. I have been experiencing difficulty getting my computer to download the 3.2 python program. My computer has Windows 8 software. What do you suggest I do to address this problem? ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Naming conventions
On 28/04/2015 08:31, Mitesh H. Budhabhatti wrote: Hello Friends, Can you please suggest good naming conventions/guidelines to following while writing Python code? Thanks. PEP 8 - Style Guide for Python Code at https://www.python.org/dev/peps/pep-0008/ -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Trouble Downloading 3.2 tutorial
On 28/04/15 00:08, O'Shea, Connor wrote: Greetings. I have been experiencing difficulty getting my computer to download the 3.2 python program. My computer has Windows 8 software. What do you suggest I do to address this problem? You don't say what kind of "trouble" nor which distribution of Python you are trying to download. If its the official python.org one then, as a Windows user I suggest you try the ActiveState site since their version includes many extra Windows features. Also you say Python v3.2 however the latest version is v3.4. Unless you have a strong reason to use 3.2 I suggest you get 3.4 instead, any 3.2 code should run under 3.4. If you are trying to download one of the "super Pythons" like Anaconda then I can't help and suggest you ask on their user fora. If none of that helps come back to us with a more detailed description of exactly what you are trying to do, where, what happens, and any error messages you see. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] pip install M2crypto
On 28/04/15 03:14, Juanald Reagan wrote: Good Evening, I am trying to install the M2crypto package via pip and receive an error. Python version is 2.7.4, any ideas on how to fix the SWIG error? Do you have SWIG installed? It should be in your repo. unable to execute swig: No such file or directory error: command 'swig' failed with exit status 1 -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] How to output dictionary data to CSV file
I have some data structured like this:
{'B002':'NRP 2014','B003':'HBB 2015'}
Basically account numbers and project names, each account number has a
project name. I represent it in a dictionary because that seemed the
best way to keep the account numbers and project names together. I want
to save that information to a file, CSV seemed the easiest format
(though I am open to suggestions if there is a better way!). I expected
I could write a function that would create a CSV file that looks like this:
B002,NRP 2014
B003,HBB 2015
I thought the DictWriter method of the CSV module should do the trick so
wrote this:
def write_fqas(fqa_csv,fqa_dict):
with open('fqa_csv','w') as csvfile:
writer = csv.DictWriter(csvfile,fieldnames=['FQA','Description']
writer.writerows(fqa_dict)
This didn't yield the results I was looking for, instead it raises
ValueError: dict contains fields not in fieldnames: 'B', '0', '0', '2'
It seems to be parsing through the key of the first item in the
dictionary rather than simply saving it to the CSV file as the first
field on a line (like I expected). Obviously there is something about
how csv.DictWriter works that I don't understand.
Any assistance is appreciated.
thomas
==
Thomas C. Hicks, MD, MPH
Training Manager, Gansu Gateway
Lanzhou, Gansu, PR China
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Re: [Tutor] How to output dictionary data to CSV file
How rude of me, I neglected to note I am using Python 3.4.3.
On 04/28/2015 04:51 PM, Paradox wrote:
I have some data structured like this:
{'B002':'NRP 2014','B003':'HBB 2015'}
Basically account numbers and project names, each account number has a
project name. I represent it in a dictionary because that seemed the
best way to keep the account numbers and project names together. I
want to save that information to a file, CSV seemed the easiest format
(though I am open to suggestions if there is a better way!). I
expected I could write a function that would create a CSV file that
looks like this:
B002,NRP 2014
B003,HBB 2015
I thought the DictWriter method of the CSV module should do the trick
so wrote this:
def write_fqas(fqa_csv,fqa_dict):
with open('fqa_csv','w') as csvfile:
writer = csv.DictWriter(csvfile,fieldnames=['FQA','Description']
writer.writerows(fqa_dict)
This didn't yield the results I was looking for, instead it raises
ValueError: dict contains fields not in fieldnames: 'B', '0', '0', '2'
It seems to be parsing through the key of the first item in the
dictionary rather than simply saving it to the CSV file as the first
field on a line (like I expected). Obviously there is something about
how csv.DictWriter works that I don't understand.
Any assistance is appreciated.
thomas
==
Thomas C. Hicks, MD, MPH
Training Manager, Gansu Gateway
Lanzhou, Gansu, PR China
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Re: [Tutor] How to output dictionary data to CSV file
Paradox wrote:
> I have some data structured like this:
>
> {'B002':'NRP 2014','B003':'HBB 2015'}
>
> Basically account numbers and project names, each account number has a
> project name. I represent it in a dictionary because that seemed the
> best way to keep the account numbers and project names together. I want
> to save that information to a file, CSV seemed the easiest format
> (though I am open to suggestions if there is a better way!). I expected
> I could write a function that would create a CSV file that looks like
> this:
>
> B002,NRP 2014
> B003,HBB 2015
>
> I thought the DictWriter method of the CSV module should do the trick so
> wrote this:
>
> def write_fqas(fqa_csv,fqa_dict):
> with open('fqa_csv','w') as csvfile:
> writer = csv.DictWriter(csvfile,fieldnames=['FQA','Description']
> writer.writerows(fqa_dict)
>
> This didn't yield the results I was looking for, instead it raises
>
> ValueError: dict contains fields not in fieldnames: 'B', '0', '0', '2'
>
> It seems to be parsing through the key of the first item in the
> dictionary rather than simply saving it to the CSV file as the first
> field on a line (like I expected). Obviously there is something about
> how csv.DictWriter works that I don't understand.
DictWriter expects a sequence of dicts where the keys are the column names.
Example:
>>> import csv
>>> import sys
>>> data = [
... {"FQA": "B002", "Description": "NRP 2014"},
... {"FQA": "B003", "Description": "HBB 2015"},
... ]
>>> writer = csv.DictWriter(sys.stdout, fieldnames=["FQA", "Description"])
>>> writer.writerows(data)
B002,NRP 2014
B003,HBB 2015
As you want to write both keys and values as a column you can pass the dict
items() to a normal csv.writer:
>>> data = {'B002':'NRP 2014','B003':'HBB 2015'}
>>> writer = csv.writer(sys.stdout)
>>> writer.writerows(data.items())
B002,NRP 2014
B003,HBB 2015
> How rude of me, I neglected to note I am using Python 3.4.3.
And now you're top-posting to make it even worse ;)
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Re: [Tutor] How to output dictionary data to CSV file :p:
On 04/28/2015 05:30 PM, Peter Otten wrote:
>>>data = {'B002':'NRP 2014','B003':'HBB 2015'}
>>>writer = csv.writer(sys.stdout)
>>>writer.writerows(data.items())
B002,NRP 2014
B003,HBB 2015
That is exactly what I was looking for! Thanks, apparently my knowledge
deficit is in understanding dictionary methods.
>How rude of me, I neglected to note I am using Python 3.4.3.
And now you're top-posting to make it even worse;)
Lesson learned!
thomas
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Re: [Tutor] How to output dictionary data to CSV file
On 28/04/15 09:51, Paradox wrote: to save that information to a file, CSV seemed the easiest format You could consider JSON too. JSON looks a lot like a Python dictionary of strings so is almost a perfect match to your data. The json module is in the standard library. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] Pythonic review (descriptors)
I'm looking for somebody willing to review parts of this code https://github.com/SageHack/cloud-buster and let me know what is not Pythonic :P I want to improve my Python coding skills but I'm not sure exactly what to study next. Right now I'm trying to use descriptors correctly and I'd like to know if this is about right https://github.com/SageHack/cloud-buster/tree/master/bust/descriptor Thanks :) ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Pythonic review (descriptors)
On 28/04/15 10:55, Sage Hack wrote:
I'm looking for somebody willing to review parts of this code
https://github.com/SageHack/cloud-buster and let me know what is not
Pythonic :P
> https://github.com/SageHack/cloud-buster/tree/master/bust/descriptor
The thing that jumps out to me is your use of class variables to hold a
dictionary of instance responses based on the instance ID. That
pattern looks like this, and you use it in every class:
class SomeClass:
classvar = {}
def __init__(self,id):
self.id = id
def __get__(self...):
v = getSomeValue()
sel.classvar[self.id] = v
Normally you'd store instance specific data in the instance
itself not in a class variable. also you overwrite the
classvariable entry for each instance every time you call
the get(). Is that really what you want?
The other thing is that you should have docstrings for
both the classes and methods.
Finally, and not Python specific, You have several classes
sharing the same 'ID' data - self.domain - that's usually
a bad OOP smell. Only one class should be mastering any
given type of data, so maybe your other classes are
really methods of whichever is the master class? Particularly
since they don't have any explicit methods (also a bad OOP
smell) of their own.
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.amazon.com/author/alan_gauld
Follow my photo-blog on Flickr at:
http://www.flickr.com/photos/alangauldphotos
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Re: [Tutor] Pythonic review (descriptors)
On 28/04/15 10:55, Sage Hack wrote:
I'm looking for somebody willing to review parts of this code
https://github.com/SageHack/cloud-buster and let me know what is not
Pythonic :P
https://github.com/SageHack/cloud-buster/tree/master/bust/descriptor
Another point re the PageTitle class:
class PageTitle(object):
titles = {}
def __init__(self, url, host=None):
self.url = url
self.host = host
def __get__(self, obj=None, objtype=None):...
@property
def id(self):
if self.host:
return self.url+':'+self.host
else:
return self.url
There is not much point in calculating the id each time,
it could simply be set in the init(). You never change
the url or host.
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.amazon.com/author/alan_gauld
Follow my photo-blog on Flickr at:
http://www.flickr.com/photos/alangauldphotos
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Re: [Tutor] Naming conventions
On Tue, Apr 28, 2015 at 01:01:04PM +0530, Mitesh H. Budhabhatti wrote: > Hello Friends, > > Can you please suggest good naming conventions/guidelines to following > while writing Python code? Thanks. Most important rule of all: names should be descriptive and understandable, not too short or cryptic, not so long that they are painful to use. Very common names may be abbreviated. Names should be easy to say aloud. # Good names length, len, map, format # Bad names a, the_thing_we_process, szty Avoid "funny" or meaningless names: pizza = 23 homework = 5 print (pizza > homework) It is acceptable to use standard one-letter variable names in generic functions, especially for algebraic (maths) functions and short utility functions, e.g.: i, j, k: integer loop variables m, n: other integers x, y: floats z: complex numbers s: string or set d: dict L: list (don't use l because it can look like 1) o: object u, v: vectors, arrays, sets are common choices. But don't over-use one-letter names. Otherwise, names should be self-descriptive: # Bad L = get_customers() # list of customers # Good customers = get_customers() Use plurals for lists, sets or dicts of some data type, and the singular for individual data types. E.g.: names = ['John', 'Mary', 'Fred', 'Sue'] for name in names: process(name) Functions and methods should be verbs or verb-phrases in all lowercase, for example: expand() sort() lift() prepare_database() create_factory() Variables holding data values should be nouns: page count header footer server client factory (Watch out for words which can be both a noun and a verb, like count.) Classes should be nouns with initial capitals: Car Engine Animal HTTPServer and instances should be lowercase: server = HTTPServer() The exception is if the class is a "small" primitive or simple type, like built-ins int, str, dict, list etc. But even then, you may choose to use Initial Capitals instead. Modules should follow the all-lowercase name. If possible, modules should describe what they are about: math string io unicodedata but it is also acceptable for modules to have an arbitrary name which you just have to learn: pillow flask zope fabric nose Does this help? -- Steve ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] Fwd: circular movement in pygame
-- Forwarded message --
From: diliup gabadamudalige
Date: Tue, Apr 28, 2015 at 6:22 PM
Subject: circular movement in pygame
To: pygame-us...@seul.org
Looking at the code on this page lines 47 & 48
http://programarcadegames.com/python_examples/show_file.php?file=sprite_circle_movement.py
is there a way to do
self.rect.x +*= some value*
self.rect.y += some value
rather than
self.rect.x = self.radius * math.sin(self.angle) + self.center_x
self.rect.y = self.radius * math.cos(self.angle) + self.center_y
?
I tired it in the code attached and strangely it works ok but only OUTSIDE
THE class. When I implement the exact code in a class it does something
weird. I can't find where I have gone wrong.
Please help.
Many thanks in advance.
Diliup Gabadamudalige
**
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not the intended recipient or have received it in error, please delete it
and all copies from your system and notify the sender immediately by return
e-mail. Any unauthorized reading, reproducing, printing or further
dissemination of this e-mail or its contents is strictly prohibited and may
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errors or omissions.
**
--
Diliup Gabadamudalige
http://www.diliupg.com
http://soft.diliupg.com/
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dissemination of this e-mail or its contents is strictly prohibited and may
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secure, error or virus-free. The sender does not accept liability for any
errors or omissions.
**
import sys, os, pygame, itertools
from math import sin,cos,pi, radians
from pygame.locals import *
os.environ['SDL_VIDEO_WINDOW_POS'] = "%d,%d" % (50,50) #Set window position
pygame.init()
clock = pygame.time.Clock()
FPS = 1000
SCREENW = 800 #screen width
SCREENH = 740 #screen height
BLACK = (0, 0, 0)
BLUE = (0, 0, 255)
ORANGE = (128, 100, 30)
FONT1= "Cookie-Regular.ttf"
SCREEN = pygame.display.set_mode((SCREENW, SCREENH), 0, 32) #display screen
clock = pygame.time.Clock()
#---
def maketext(msg,fontsize, colour = ORANGE, font = FONT1):
mafont = pygame.font.Font(font, fontsize)
matext = mafont.render(msg, True, colour)
matext = matext.convert_alpha()
return matext
#---
def print_info():
""
textcos = maketext(str(round(obj.rect.x, 2)) + " " +
str(round(obj.rect.y, 2)), 30)
SCREEN.blit(textcos, (obj.rect.x, obj.rect.y + 30))
#---
class object_factory(pygame.sprite.Sprite):
def __init__(self, imagelist, xpos = 0, ypos = 0, speedx = 0, speedy = 0,
value = 0):
"""Constructor"""
pygame.sprite.Sprite.__init__(self)
self.name = ""
self.frame = 0
self.imagelist = imagelist
self.image = imagelist[self.frame]
self.mask = pygame.mask.from_surface(self.image) # pixelmask
self.rect = self.image.get_rect()
self.rect.x = xpos
self.rect.y = ypos
self.speedx = speedx
self.speedy = speedy
self.timer = 0
self.timerlimit = 10
#--
def move(self): # wallsprites, Herosprite, looptime
self.rect.x += self.speedx
self.rect.y += self.speedy
#--
def update(self):
""
self.image = self.imagelist[self.frame]
if self.timer >= self.timerlimit:
self.frame += 1
if self.frame >= len(self.imagelist):
self.frame = 0
self.timer = 0
self.timer += 1
plat = pygame.image.load("plt0.png").convert_alpha()
star = pygame.image.load("gemp0.png").convert_alpha()
box = pygame.image.load("crateB.png").convert_alpha()
platforms = pygame.sprite.Group()
boxes = pygame.sprite.Group()
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Re: [Tutor] Fwd: circular movement in pygame
On 28/04/15 16:38, diliup gabadamudalige wrote: -- Forwarded message -- From: diliup gabadamudalige Date: Tue, Apr 28, 2015 at 6:22 PM Subject: circular movement in pygame To: pygame-us...@seul.org It's good that you tried the python-game list for a pygame question. But if pygame-users can't give a definitive answer then its even less likely that the tutor list will. Although you might need to allow a full 24 hours to get answers, email is not an instant delivery mechanism. Looking at the code on this page lines 47 & 48 http://programarcadegames.com/python_examples/show_file.php?file=sprite_circle_movement.py I didn't look at the code in that tutorial, but... is there a way to do self.rect.x +*= some value* self.rect.y += some value Yes, that's just normal Python syntax. It adds/multiplies the current value of self.rect with "some value"... rather than self.rect.x = self.radius * math.sin(self.angle) + self.center_x self.rect.y = self.radius * math.cos(self.angle) + self.center_y But its unlikely to have the same effect as this since the above two lines are calculating a new value based on radius, angle, and centre rather than one based on the current values of self.rect I tired it in the code attached and strangely it works ok but only OUTSIDE THE class. When I implement the exact code in a class it does something weird. I can't find where I have gone wrong. I can't see your code but are you sure you are using self in all the appropriate places in your class based code? -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Fwd: circular movement in pygame
On 28 April 2015 at 16:38, diliup gabadamudalige wrote: > > Looking at the code on this page lines 47 & 48 > > http://programarcadegames.com/python_examples/show_file.php?file=sprite_circle_movement.py > > is there a way to do > self.rect.x +*= some value* > self.rect.y += some value > > rather than > > self.rect.x = self.radius * math.sin(self.angle) + self.center_x > self.rect.y = self.radius * math.cos(self.angle) + self.center_y There's no way to do that. The second version ignores the previous value of self.rect.x/y. I'm going to guess that the angle has only changed by a small amount delta_angle between iterations in which case there would be a way to do it approximately. The real question is just why though? The second version is correct and will be correct for ever. The first version would only be approximately correct and over time you'd probably find that the position would drift so that the ball was effectively at a different radius. In any case if x = r * sin(theta) then dx/dt = r * cos(theta) * dtheta/dt. Since y = r * cos(theta) that's dy/dt = x * dtheta/dt. So you could update y approximately with: y += x * dtheta/dt * deltat where deltat is your timestep. In your code that would be: self.rect.x += self.rect.y * self.speed self.rect.y -= self.rect.x * self.speed Really what you have now is better though. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Fwd: circular movement in pygame
On 28 April 2015 at 19:37, diliup gabadamudalige wrote:
>
> I thank all those who responded to my question
>
> Here is the code that I had written.
>
> When updating is applied to a surface object the rotation works but when it
> is applied through a class to an object it goes wrong in about 3 rotations.
> As far as I can see the code is the same. What is wrong? If you can correct
> some code and show me would help.
Your code is too long and complicated for me to read through it all.
You should simplify your problem before posting it somewhere like
this. Make a simpler program that does something similar but without
all the pygame stuff. For example your program might just loop through
printing out the positions of the object at different times e.g.:
# game.py
#
# This program simulates a ball moving at constant speed
# in a two dimensional space.
#
# Initial position of ball
xpos = 0
ypos = 0
# Horizontal and vertical speed
xspeed = 1
yspeed = 2
# Timestep
deltat = 0.125
# Run through 10 iterations of simulation
for n in range(10):
# Update state
xpos += xspeed * deltat
ypos += yspeed * deltat
# Output current state
print('Position = (%.3f, %.3f)' % (xpos, ypos))
$ python game.py # Show the output
Position = (0.125, 0.250)
Position = (0.250, 0.500)
Position = (0.375, 0.750)
Position = (0.500, 1.000)
Position = (0.625, 1.250)
Position = (0.750, 1.500)
Position = (0.875, 1.750)
Position = (1.000, 2.000)
Position = (1.125, 2.250)
Position = (1.250, 2.500)
Once you have made a simpler program carefully explain what it is that
you want it to do and show us how what it does is different. Don't
expect people on this list to download your code and run it.
Also please put your code in the email and not in an attachment and
please reply back to the tutor list rather than directly to me.
--
Oscar
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Re: [Tutor] Fwd: circular movement in pygame
I thank all those who responded to my question Here is the code that I had written. When updating is applied to a surface object the rotation works but when it is applied through a class to an object it goes wrong in about 3 rotations. As far as I can see the code is the same. What is wrong? If you can correct some code and show me would help. On Tue, Apr 28, 2015 at 11:58 PM, Oscar Benjamin wrote: > On 28 April 2015 at 16:38, diliup gabadamudalige > wrote: > > > > Looking at the code on this page lines 47 & 48 > > > > > http://programarcadegames.com/python_examples/show_file.php?file=sprite_circle_movement.py > > > > is there a way to do > > self.rect.x +*= some value* > > self.rect.y += some value > > > > rather than > > > > self.rect.x = self.radius * math.sin(self.angle) + self.center_x > > self.rect.y = self.radius * math.cos(self.angle) + self.center_y > > There's no way to do that. The second version ignores the previous > value of self.rect.x/y. > > I'm going to guess that the angle has only changed by a small amount > delta_angle between iterations in which case there would be a way to > do it approximately. > > The real question is just why though? The second version is correct > and will be correct for ever. The first version would only be > approximately correct and over time you'd probably find that the > position would drift so that the ball was effectively at a different > radius. > > In any case if > x = r * sin(theta) > then > dx/dt = r * cos(theta) * dtheta/dt. > Since > y = r * cos(theta) that's > dy/dt = x * dtheta/dt. > So you could update y approximately with: > y += x * dtheta/dt * deltat > where deltat is your timestep. In your code that would be: > self.rect.x += self.rect.y * self.speed > self.rect.y -= self.rect.x * self.speed > > Really what you have now is better though. > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor > -- Diliup Gabadamudalige http://www.diliupg.com http://soft.diliupg.com/ ** This e-mail is confidential. It may also be legally privileged. If you are not the intended recipient or have received it in error, please delete it and all copies from your system and notify the sender immediately by return e-mail. Any unauthorized reading, reproducing, printing or further dissemination of this e-mail or its contents is strictly prohibited and may be unlawful. Internet communications cannot be guaranteed to be timely, secure, error or virus-free. The sender does not accept liability for any errors or omissions. ** import sys, os, pygame, itertools from math import sin,cos,pi, radians from pygame.locals import * os.environ['SDL_VIDEO_WINDOW_POS'] = "%d,%d" % (50,50) #Set window position pygame.init() clock = pygame.time.Clock() FPS = 1000 SCREENW = 800 #screen width SCREENH = 740 #screen height BLACK = (0, 0, 0) BLUE = (0, 0, 255) ORANGE = (128, 100, 30) FONT1= "Cookie-Regular.ttf" SCREEN = pygame.display.set_mode((SCREENW, SCREENH), 0, 32) #display screen clock = pygame.time.Clock() #--- def maketext(msg,fontsize, colour = ORANGE, font = FONT1): mafont = pygame.font.Font(font, fontsize) matext = mafont.render(msg, True, colour) matext = matext.convert_alpha() return matext #--- def print_info(): "" textcos = maketext(str(round(obj.rect.x, 2)) + " " + str(round(obj.rect.y, 2)), 30) SCREEN.blit(textcos, (obj.rect.x, obj.rect.y + 30)) #--- class object_factory(pygame.sprite.Sprite): def __init__(self, imagelist, xpos, ypos, speedx = 0, speedy = 0, value = 0): """Constructor""" pygame.sprite.Sprite.__init__(self) self.name = "" self.frame = 0 self.imagelist = imagelist self.image = imagelist[self.frame] self.mask = pygame.mask.from_surface(self.image) # pixelmask self.rect = self.image.get_rect() self.rect.x = xpos self.rect.y = ypos #self.speedx = speedx #self.speedy = speedy self.timer = 0 self.timerlimit = 10 #-- #def move(self): # wallsprites, Herosprite, looptime #self.rect.x += self.speedx #self.rect.y += self.speedy #-- def update(self): "" self.image = self.imagelist[self.frame] if self.timer >= self.timerlimit: s
Re: [Tutor] How to output dictionary data to CSV file :p:
On 04/28/2015 09:43 PM, Alan Gauld wrote: You could consider JSON too. JSON looks a lot like a Python dictionary of strings so is almost a perfect match to your data. Sounds great, I'll check it out. Thanks! thomas == Thomas C. Hicks, MD, MPH Training Manager, Gansu Gateway Lanzhou, Gansu, PR China ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Fwd: circular movement in pygame
On 04/28/2015 02:37 PM, diliup gabadamudalige wrote: I thank all those who responded to my question Here is the code that I had written. When updating is applied to a surface object the rotation works but when it is applied through a class to an object it goes wrong in about 3 rotations. As far as I can see the code is the same. What is wrong? If you can correct some code and show me would help. By top-posting, you're messing up the readability of your response. And by trying to use an attachment, you're messing up a large portion of the people reading this thread. Post a simplified example, inline in your message, and *following* any quote you're using. If your symptom is that the data diverges eventually from the intended trajectory, the problem is that you're accumulating errors. Each point you do you're rounding the calculation by storing it in finite precision. After enough roundoffs, the error becomes visible. If you need to reliably move an object in a circle, you'll want to store the location in angular terms, center, radius, and angle. Then each time around the loop, increment the angle by a non-rounded amount, and recalculate the x/y coordinates. -- DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] Good Taste Question: Using SQLite3 in Python
Hello, all.. I have a class with methods that access a database (SQLite3). I have included an excerpt showin reading and writing and would like to know if I'm doing it right. (i.e: Is it bad code and what to improve). Here are some improvements and my rationale (check my thinking): - Initially, each method had its SQL statement(s) inside, but I grouped all statements in a dictionary, with operations as keys, as a class 'constant' as per previous advice on this mailing list. - Each method used sqlite3 module on its own, but it was repetitive so I put that part in its own method `init_db` that returns a tuple consisting in a connection and a cursor. - Sometimes there was an exception raised, so I used `try` in `init_db`. - Methods closed the connection themselves, so I used `with` in `init_db` instead of `try`, as it would close the connection automatically and rollback (I hope I'm not making this up). Here's the excerpt (`DB_FILES` and `QUERIES` are not included here for more clarity). Thank you. def __init__(self, phone): # Get preliminary information on user and make them # available. self.phone = phone self.known = self.find() if self.known: self.balance = self.get_balance() else: self.balance = None def init_db(self): with sqlite3.connect(self.DB_FILE) as conn: return conn, conn.cursor() def find(self): '''Find the phone in the users database.''' (__, cursor) = self.init_db() try: cursor.execute( self.QUERIES['FIND_PHONE'], (self.phone,) ) found = cursor.fetchone() return True if found else False except Exception as e: return self.ERROR.format(e.args[0]) def create(self, seed_balance): ''' Create a database entry for the sender.''' conn, cursor = self.init_db() try: cursor.execute( self.QUERIES['CREATE'], (self.phone, seed_balance) ) conn.commit() except Exception as e: return self.ERROR.format(e.args[0]) -- ~Jugurtha Hadjar, ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] Function works one time then subsequently fails
This is really puzzling me. I'm parsing a string to do some simple math
operations and practice tossing functions around. My parser works on the
first run, then it continually fails on the same input.
"""
Takes the name of a binary math operation and two numbers from input,
repeatedly, and displays the results until done
"""
def add(a, b):
return a + b
def subtract(a, b):
return b - a
def minus(a, b):
return a - b
def multiply(a, b):
return a * b
def divide(a, b):
return a / b
operations = {'add': add, '+': add, 'plus': add, 'subtract': subtract,
'-': minus, 'minus': minus, 'multiply': multiply, '*':
multiply,
'times': multiply, 'divide': divide, '/': divide,
'divided': divide}
numbers = []
def test_number(astring):
"""
Input: A string that should represent a valid int or float. Output:
An int or float on success. None on failure.
"""
for make_type in (int, float):
try:
return make_type(astring)
except ValueError:
pass
return None
def parse_string(math_string):
"""Input: A math string with a verbal or mathematical operation
and two valid numbers to operate on. Extra numbers and operations
are ignored. Output: A tuple containing a function corresponding
to the operation and the two numbers. Returns None on failure.
"""
operation = None
tokens = math_string.split()
for token in tokens:
if token in operations:
operation = operations[token]
elif test_number(token) != None:
numbers.append(test_number(token))
if len(numbers) > 1:
break
if operation is None or len(numbers) < 2:
return None
else:
return operation, numbers[0], numbers[1]
REPL
>>> result = parse_string('1 minus 15')
>>> func, number1, number2 = result
>>> func(number1, number2)
-14
>>> result = parse_string('1 minus 15')
>>> print(result)
None
>>> result = parse_string('1 minus 15')
>>> print(result)
None
>>>
--
Jim
If you only had one hour left to live, would you spend it on Facebook,
Twitter, or Google Plus?
___
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Re: [Tutor] Function works one time then subsequently fails
On 28Apr2015 20:58, Jim Mooney Py3winXP wrote: This is really puzzling me. I'm parsing a string to do some simple math operations and practice tossing functions around. My parser works on the first run, then it continually fails on the same input. [...] numbers = [] [...] def parse_string(math_string): """Input: A math string with a verbal or mathematical operation and two valid numbers to operate on. Extra numbers and operations are ignored. Output: A tuple containing a function corresponding to the operation and the two numbers. Returns None on failure. """ operation = None tokens = math_string.split() for token in tokens: if token in operations: operation = operations[token] elif test_number(token) != None: numbers.append(test_number(token)) if len(numbers) > 1: break [...] At a first glance numbers is a global. It is reset to [] at program start, but never again. So you're appending to it forever. I have not investigated further as to how that affects your program's flow. Cheers, Cameron Simpson There are two ways of dealing with this problem: one is complicated and messy, and the other is simple and very elegant. We don't have much time left, so I'll just show you the complicated and messy way. - Richard Feynman, 1981 ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Function works one time then subsequently fails
On 28 April 2015 at 21:27, Cameron Simpson wrote: > At a first glance numbers is a global. It is reset to [] at program start, > but never again. So you're appending to it forever. I have not investigated > further as to how that affects your program's flow. > > Cheers, > Cameron Simpson > Took you less time to find that than me. I, of course, realized I forgot to empty the number list on each time through the parse loop, After I posted ;') Seems to work okay otherwise, although criticism of Pythonicity is welcome. I just wanted to practice tossing functions around. I'll put it into a user input loop and work it. It won't catch everything. I have to study regexes for that. At this point I'm starting to lose track and have to think of better ways to organize so I recall and understand what I'm doing. I know there are general tuts on that but that's just reading. Is there a python-specific tut on it where I could follow actual code along with the interpreter to reinforce things? Or, what is the official word for organize-so-you-don't-forget-or-get-confused so I can search google with it? -- Jim If you only had one hour left to live, would you spend it on Facebook, Twitter, or Google Plus? ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Naming conventions
Thank you so much Mark, Steven. This will definitely help. I really appreciate. On Tue, Apr 28, 2015 at 8:45 PM, Steven D'Aprano wrote: > On Tue, Apr 28, 2015 at 01:01:04PM +0530, Mitesh H. Budhabhatti wrote: > > Hello Friends, > > > > Can you please suggest good naming conventions/guidelines to following > > while writing Python code? Thanks. > > Most important rule of all: names should be descriptive and > understandable, not too short or cryptic, not so long that they are > painful to use. Very common names may be abbreviated. Names should be > easy to say aloud. > > # Good names > length, len, map, format > > # Bad names > a, the_thing_we_process, szty > > Avoid "funny" or meaningless names: > > pizza = 23 > homework = 5 > print (pizza > homework) > > > It is acceptable to use standard one-letter variable names in > generic functions, especially for algebraic (maths) functions and > short utility functions, e.g.: > > i, j, k: integer loop variables > m, n: other integers > x, y: floats > z: complex numbers > s: string or set > d: dict > L: list (don't use l because it can look like 1) > o: object > u, v: vectors, arrays, sets > > are common choices. But don't over-use one-letter names. > > Otherwise, names should be self-descriptive: > > # Bad > L = get_customers() # list of customers > > # Good > customers = get_customers() > > Use plurals for lists, sets or dicts of some data type, and the singular > for individual data types. E.g.: > > names = ['John', 'Mary', 'Fred', 'Sue'] > for name in names: > process(name) > > > Functions and methods should be verbs or verb-phrases in all lowercase, > for example: > > expand() sort() lift() prepare_database() create_factory() > > Variables holding data values should be nouns: > >page count header footer server client factory > > (Watch out for words which can be both a noun and a verb, like count.) > > Classes should be nouns with initial capitals: > > Car Engine Animal HTTPServer > > and instances should be lowercase: > > server = HTTPServer() > > The exception is if the class is a "small" primitive or simple type, > like built-ins int, str, dict, list etc. But even then, you may choose > to use Initial Capitals instead. > > Modules should follow the all-lowercase name. If possible, modules > should describe what they are about: > > math string io unicodedata > > but it is also acceptable for modules to have an arbitrary name which > you just have to learn: > > pillow flask zope fabric nose > > > > Does this help? > > > -- > Steve > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor > ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Function works one time then subsequently fails
On 28Apr2015 22:27, Jim Mooney Py3winXP wrote: On 28 April 2015 at 21:27, Cameron Simpson wrote: At a first glance numbers is a global. It is reset to [] at program start, but never again. So you're appending to it forever. I have not investigated further as to how that affects your program's flow. Took you less time to find that than me. I, of course, realized I forgot to empty the number list on each time through the parse loop, After I posted ;') Seems to work okay otherwise, although criticism of Pythonicity is welcome. I just wanted to practice tossing functions around. I'll put it into a user input loop and work it. It won't catch everything. I have to study regexes for that. Basicly, you should almost never have a global variable. There is a host of special circumstances where globals solve some specific problems. But by and large, don't do it without a very concrete reason. If numbers had been local to the parse function you would never have been bitten by this. There's no need for it to be global; you can return the operator and the operands (numbers) easily from the parse function. At this point I'm starting to lose track and have to think of better ways to organize so I recall and understand what I'm doing. I know there are general tuts on that but that's just reading. Is there a python-specific tut on it where I could follow actual code along with the interpreter to reinforce things? Or, what is the official word for organize-so-you-don't-forget-or-get-confused so I can search google with it? "functional decomposition"? One rule of thumb is that functions should be short. That way you can generally keep their purpose and internal oparations in your head in one go, and the whole thing also fits on your screen. As with all things, sometimes that cannot be reasonably achieved, but it is usually so. We can pick over your code as well if you like. Should we? Cheers, Cameron Simpson If this experiment we're doing works, then I will follow up and push it as hard as possible. And if it doesn't work, I will write a science-fiction novel where it does work. It's a win-win situation. - John Cramer on his experiment for possible cuasality violation ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
