Re: [Tutor] plotting pixels

On Sat, Sep 18, 2010 at 9:26 PM, Bill Allen wrote: > > >> Digging a little deeper it seems the idiomatic way to do this in Python >> is to use PIL the Python Imaging Library to create a GIF or bitmap >> image and then insert that into Tkinters cancvas as an image object. >> >> The Pil ImageDraw c

Re: [Tutor] plotting pixels

> > Digging a little deeper it seems the idiomatic way to do this in Python > is to use PIL the Python Imaging Library to create a GIF or bitmap > image and then insert that into Tkinters cancvas as an image object. > > The Pil ImageDraw class has a point() ethod > > I've never tried this but it is

Re: [Tutor] plotting pixels

> It appears that the Tk canvas widget does not support simply plotting a >pixel. > Correct, and I agree it seems odd, but in practice drawing either lines or ovals of one-pixel do the equivalent job - albeit a little more slowly. > The primitive obviously exists in the underlying code, I

Re: [Tutor] plotting pixels

On Sat, Sep 18, 2010 at 1:18 PM, Ken Oliver wrote: > > >> On Fri, Sep 17, 2010 at 3:38 AM, Alan Gauld wrote: >> >>> >>> For plotting pixels I would not use turtle graphics. >>> That would be a fairly complicated option I'd have thought. >>> A simple canvas would be easier. >>> >>> Alan G. >>> >>>

Re: [Tutor] What are "singletons" good for?

On 09/19/10 02:50, Knacktus wrote: > Hey all, > > the usual explanation for the usage of a Singleton goes like this: > > "Use a singleton if you want to make sure, that only one instance of a > class exists." > > But now I ask myself: Why should I call the constructor of a class more > than once

Re: [Tutor] plotting pixels

> It appears that the Tk canvas widget does not support simply > plotting a pixel. However, I can plot a line only one pixel long. > I wonder why they do not simply provide the pixel plot primitive? I > have seen very many graphics packages that do this and I have always >

Re: [Tutor] plotting pixels

-Original Message- From: Bill Allen Sent: Sep 18, 2010 11:45 AM To: Alan Gauld Cc: tutor@python.org Subject: Re: [Tutor] plotting pixels On Sat, Sep 18, 2010 at 10:44 AM, Bill Allen wrote: On Fri, Sep 17, 2010 at 3:38 AM, Alan Gauld wrot

Re: [Tutor] next class problem

> Date: Sat, 18 Sep 2010 13:40:55 -0400 > From: bgai...@gmail.com > To: rwob...@hotmail.com > CC: tutor@python.org > Subject: Re: [Tutor] next class problem > > On 9/18/2010 1:20 PM, Roelof Wobben wrote: >> >> Hello, >> >> I have this exercise : >> >> Rew

Re: [Tutor] next class problem

On 9/18/2010 1:20 PM, Roelof Wobben wrote: Hello, I have this exercise : Rewrite the distance function from chapter 5 so that it takes two Points as parameters instead of four numbers. I have this solution : class Point: def __init__(self, x=0, y=0): self.x = x se

[Tutor] next class problem

Hello, I have this exercise : Rewrite the distance function from chapter 5 so that it takes two Points as parameters instead of four numbers. I have this solution : class Point: def __init__(self, x=0, y=0): self.x = x self.y = y def distance(p1,p2): dx

Re: [Tutor] Remove a dictionary entry

Yet another way is to iterate thru the dict collecting a list of keys of items to be deleted. Then iterate thru that list deleting from the dict. -- Bob Gailer 919-636-4239 Chapel Hill NC ___ Tutor maillist - Tutor@python.org To unsubscribe or cha

[Tutor] What are "singletons" good for?

Hey all, the usual explanation for the usage of a Singleton goes like this: "Use a singleton if you want to make sure, that only one instance of a class exists." But now I ask myself: Why should I call the constructor of a class more than once if I only want one instance? After all, I decide

[Tutor] FW: class problem

Hello , Thanks everyone. I solved it by this : class Point: def __init__(self, x=0, y=0): self.x = x self.y = y P=Point() print P print id(P) and a calculator which can convert hex to decimal. Roelof > >> From: st...@pearwood.info

Re: [Tutor] Help - importing modules

On Sat, Sep 18, 2010 at 11:46 AM, Steven D'Aprano wrote: > On Sun, 19 Sep 2010 12:16:47 am Fernando Karpinski wrote: >>    Hi, everyone. I need help when importing a file I created, with >> the .py extension. I am trying to access its directory in DOS, and >> after I do it, I type "import filename

Re: [Tutor] Remove a dictionary entry

On Sat, 18 Sep 2010 07:13:13 pm Peter Otten wrote: > You should never iterate over a list or dictionary and add or remove > items to it at the same time. That is a recipe for disaster even if > it doesn't fail explicitly. That's a bit strong. It's quite possible to modify lists safely and correc

Re: [Tutor] class problem

On Sat, 18 Sep 2010 07:14:03 pm Roelof Wobben wrote: > P=(Point) This line does not do what you think it does. Brackets in Python are used for two things, grouping and calling functions. To call a function, or a class, you need to have the brackets *after* the function: P = Point() # what ab

Re: [Tutor] Help - importing modules

On Sun, 19 Sep 2010 12:16:47 am Fernando Karpinski wrote: >Hi, everyone. I need help when importing a file I created, with > the .py extension. I am trying to access its directory in DOS, and > after I do it, I type "import filename", but it is not working. Define "not working". My crystal ba

Re: [Tutor] plotting pixels

On Sat, Sep 18, 2010 at 10:44 AM, Bill Allen wrote: > > > On Fri, Sep 17, 2010 at 3:38 AM, Alan Gauld wrote: > >> >> For plotting pixels I would not use turtle graphics. >> That would be a fairly complicated option I'd have thought. >> A simple canvas would be easier. >> >> Alan G. >> >> > Oh, I

Re: [Tutor] plotting pixels

On Fri, Sep 17, 2010 at 3:38 AM, Alan Gauld wrote: > > For plotting pixels I would not use turtle graphics. > That would be a fairly complicated option I'd have thought. > A simple canvas would be easier. > > Alan G. > > Oh, I see! I did not realize that Tk had a canvas widget. That is nice. I

Re: [Tutor] class problem

"Roelof Wobben" wrote Create and print a Point object, and then use id to print the object’s unique identifier. Translate the hexadecimal form into decimal and confirm that they match. I initially had no idea what hexadecimal form the text is talking about. id returns a decimal form... T

Re: [Tutor] Remove a dictionary entry

"Alan Gauld" wrote I ended up with this : Version 3 : for i,row in d[:].iteritems() : # BUG : TypeError: unhashable type if len(row) < 2 : del d[i] You are getting too complicated. You don't need the slice and you don't need iteritems. You have a dictionary. When you iterate over

Re: [Tutor] Help - importing modules

On Sat, Sep 18, 2010 at 10:16 AM, Fernando Karpinski wrote: > >Hi, everyone. I need help when importing a file I created, with the .py > extension. I am trying to access its directory in DOS, and after I do it, I > type "import filename", but it is not working. I tried to do it by writing > "i

[Tutor] Help - importing modules

Hi, everyone. I need help when importing a file I created, with the .py extension. I am trying to access its directory in DOS, and after I do it, I type "import filename", but it is not working. I tried to do it by writing "import filename.py", but it didn't work either. I'm aware that after the

[Tutor] class problem

Hello, I have this exercise : Create and print a Point object, and then use id to print the object’s unique identifier. Translate the hexadecimal form into decimal and confirm that they match. So I thought that this would solve it: class Point: def __init__(self, x=0, y=0): self.x

Re: [Tutor] Remove a dictionary entry

M. 427 wrote: > (I am very new to python) > I built a dictionary d={} of lists similar to this : > > d = { > 'a': ['apricot', 'apple'], > 'b': ['beach', 'bear', 'bottle'], > 'c': ['cold', 'cook', 'coleslaw'], > 'd': ['deep'], > 'e': ['expression', 'elephant'] > } > > Now i want to go through thi

Re: [Tutor] Remove a dictionary entry

"M. 427" <4...@free.fr> wrote I ended up with this : Version 3 : for i,row in d[:].iteritems() : # BUG : TypeError: unhashable type if len(row) < 2 : del d[i] You are getting too complicated. You don't need the slice and you don't need iteritems. You have a dictionary. When you ite

Re: [Tutor] Remove a dictionary entry

Thank you, After reading the following documentations http://docs.python.org/tutorial/datastructures.html#looping-techniques http://docs.python.org/tutorial/controlflow.html#for-statements I ended up with this : Version 3 : for i,row in d[:].iteritems() : # BUG : TypeError: unhashable type if