Re: [Tutor] Misunderstanding the Entry Widget
Title: Signature.html
Very good. Thanks.
(I posted this about 20 hours ago with an image of my screen output. It
appears it's waiting for moderator approval, so I'm posting it again
w/o the image. Maybe the image will show up later. I think some
progress can be made with out it. )
Well, the idea of using Entry1,2 logic hit a snag. First, the program
has an oddity that I do not understand. Here's the problem area. See
the highlighted code stuff in purple and bold at the bottom. Above
that code, it's forming buttons and so on with no return object from
anywhere, then "entry = Entry(master, width=10, ..." appears. I put
some debug code in there, and ended it wih a return of entry before
20-30 lines of code using Label, etc. that use no assignment to any
object. After that is the original return entry. It's puzzling why it
returns just entry. I suspect that should cause the return to be a
OperationalSettingsDialog object; however, when I print the object and
its type, they are None, and type 'NoneType'.
REMOVED IMAGE HERE. It shows the None-NoneType msg and other Python
msgs.
class OperationalSettingsDialog(tkSimpleDialog.Dialog):
def __init__(self, parent, sdict):
self.sdict = sdict
print "Set OSDiag sdict"
print
tkSimpleDialog.Dialog.__init__(self, parent)
def body(self,master):
self.title("Operational Settings")
print "body from OSDialog, self =", self, "type =", type(self)
self.colorVar = IntVar()
Radiobutton( master, text="Gray Scale",
value=1, variable=self.colorVar).grid(row=0,
sticky=W)
Radiobutton( master, text="Pseudo Color",
value=2, variable=self.colorVar).grid(row=1,
sticky=W)
self.colorVar.set( self.sdict["color"] )
self.post_event_stackVar = IntVar()
Checkbutton( master, text="Make long exposure after each event",
variable=self.post_event_stackVar).grid(row=2,
sticky=W)
self.post_event_stackVar.set( self.sdict["post_event_stack"] )
self.show_real_timeVar = IntVar()
Checkbutton( master, text="Show event as it is being received",
variable=self.show_real_timeVar).grid(row=3,
sticky=W)
self.show_real_timeVar.set( self.sdict["show_real_time"] )
Label( master, text="Playback Slowdown: ").grid(row=4, stick=W)
self.slowdownVar = StringVar()
# entry = Entry(master, width=10,
textvariable=self.slowdownVar).grid(row=4, column=1)
entry = Entry(master, width=10).grid(row=4, column=1)
print "entry, entry type:", entry,type(entry)
entry.insert(0,self.slowdown)
slowdown = entry
print "holly cow: ",slowdown
#self.slowdownVar.set( "%d" % self.sdict["slowdown"] )
return entry
Alan Gauld wrote:
"Alan Gauld" alan.ga...@btinternet.com
wrote
Yep, when I bowed of programming long ago,
I had Ousterhout's
It was a good book in its day but is now well overdue an update.
And lo and behold, listed on Amazon is the 2nd edition due in August
2009!
How's that for service :-)
BTW I also noticed that there is also now an O'Reilly pocket reference
which might be even more useful to Python Tkinter users than the
Nutshell - smaller and cheaper and even more terse! Although it doesn't
appear to cover Tix...
Alan G.
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--
Wayne Watson (Watson Adventures, Prop., Nevada City, CA)
(121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time)
In mathematics you don't understand things.
You just get used to them. -- John Von Neumann
(P.S. The same is true in life.)
Web Page: www.speckledwithstars.net/
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Re: [Tutor] Misunderstanding the Entry Widget
Title: Signature.html I had commented out # entry = Entry(master, width=10, textvariable=self.slowdownVar).grid(row=4, column=1), which had worked fine previously to my changes. I added your two statements after remarking entry = Entry(master, width=10).grid(row=4, column=1) IDLE the Command prompt window produced, which was really what I was showing in the image that I removed: Exception in Tkinter callback Traceback (most recent call last): File "C:\Python25\Lib\lib-tk\Tkinter.py", line 1403, in __call__ return self.func(*args) File "C:\Sandia_Meteors\Sentinel_Development\Development_Sentuser-Utilities\sentuser\sentuserNC25-Dev5.py", line 579, in OperationalSettings dialog = OperationalSettingsDialog( self.master, set_loc_dict ) File "C:\Sandia_Meteors\Sentinel_Development\Development_Sentuser-Utilities\sentuser\sentuserNC25-Dev5.py", line 84, in __init__ tkSimpleDialog.Dialog.__init__(self, parent) File "C:\Python25\lib\lib-tk\tkSimpleDialog.py", line 64, in __init__ self.initial_focus = self.body(body) File "C:\Sandia_Meteors\Sentinel_Development\Development_Sentuser-Utilities\sentuser\sentuserNC25-Dev5.py", line 115, in body entry.insert(0,self.slowdown) AttributeError: OperationalSettingsDialog instance has no attribute 'slowdown' Kent Johnson wrote: On Mon, Mar 9, 2009 at 8:30 AM, Wayne Watson sierra_mtnv...@sbcglobal.net wrote: entry = Entry(master, width=10).grid(row=4, column=1) You have to write this as entry = Entry(master, width=10) entry.grid(row=4, column=1) The grid() method returns None, that is why entry is None. Kent -- Wayne Watson (Watson Adventures, Prop., Nevada City, CA) (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time) In mathematics you don't understand things. You just get used to them. -- John Von Neumann (P.S. The same is true in life.) Web Page: www.speckledwithstars.net/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
Title: Signature.html On a branch off this thread, I've mentioned a problem with this approach. It seems right, but I haven't bridged it yet. Do you have some simple Tk Python code that shows how to do this? Alan Gauld wrote: "Wayne Watson" sierra_mtnv...@sbcglobal.net wrote Signature.htmlAnother thought occurred to me about this situation. Suppose I have a dialog with two Entry objects in a dialog object called TwoEntries: entry1 = Entry(master, width=10).grid(row=4, column=1) entry2 = Entry(master, width=10).grid(row=5, column=1) and I do not use a StringVar to return the values entered. Is it possible to reach inside TwoEntries, after returning from it, and grab entry1 and 2? It would seem so if the call was dialog=TwoEntries(...). Sure, just use x = dialog.entry1.get() y = dialog.entry2.get() There really is nothing special going on. I have no idea of the history of these variables, but they have very limited descriptions and examples. I assume because they have a very simple and specific purpose. There is probably more on them if you look at the original Tcl/Tk documentation. Remember Tkinter is just a wrapper arpund Tcl/Tkl and Tk has been around for a long time (20 years now) Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor -- Wayne Watson (Watson Adventures, Prop., Nevada City, CA) (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time) In mathematics you don't understand things. You just get used to them. -- John Von Neumann (P.S. The same is true in life.) Web Page: www.speckledwithstars.net/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
Wayne Watson sierra_mtnv...@sbcglobal.net wrote Signature.htmlAnother thought occurred to me about this situation. Suppose I have a dialog with two Entry objects in a dialog object called TwoEntries: entry1 = Entry(master, width=10).grid(row=4, column=1) entry2 = Entry(master, width=10).grid(row=5, column=1) and I do not use a StringVar to return the values entered. Is it possible to reach inside TwoEntries, after returning from it, and grab entry1 and 2? It would seem so if the call was dialog=TwoEntries(...). Sure, just use x = dialog.entry1.get() y = dialog.entry2.get() There really is nothing special going on. I have no idea of the history of these variables, but they have very limited descriptions and examples. I assume because they have a very simple and specific purpose. There is probably more on them if you look at the original Tcl/Tk documentation. Remember Tkinter is just a wrapper arpund Tcl/Tkl and Tk has been around for a long time (20 years now) Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
Title: Signature.html Thanks. Your statement is reassuring. Without trying to give my self a pat on the back, exactly written as I figured. It seems so very obvious, but the lack of attention to using that style makes one wonder why it isn't commonly found anywhere in the discussion of more complex collection of widgets (see my other comments below). In my case, really following the author's (of 2000 lines of code I have) makes me wonder why he didn't do it that way. I suspect the answer is he had recently taken a Python class before writing it, and was following what simply was taught to get this program completed. (It is not a classroom program.) I know he put it together quickly, and did quite a spectacular job of writing the code and interfacing it to some complex h/w. Alan Gauld wrote: "Wayne Watson" sierra_mtnv...@sbcglobal.net wrote Signature.htmlAnother thought occurred to me about this situation. Suppose I have a dialog with two Entry objects in a dialog object called TwoEntries: entry1 = Entry(master, width=10).grid(row=4, column=1) entry2 = Entry(master, width=10).grid(row=5, column=1) and I do not use a StringVar to return the values entered. Is it possible to reach inside TwoEntries, after returning from it, and grab entry1 and 2? It would seem so if the call was dialog=TwoEntries(...). Sure, just use x = dialog.entry1.get() y = dialog.entry2.get() There really is nothing special going on. I have no idea of the history of these variables, but they have very limited descriptions and examples. I assume because they have a very simple and specific purpose. There is probably more on them if you look at the original Tcl/Tk documentation. Remember Tkinter is just a wrapper arpund Tcl/Tkl and Tk has been around for a long time (20 years now) Yep, when I bowed of programming long ago, I had Ousterhout's (something like that) book, and finally sold it on Amazom 5 years ago with the thought I have no plan to use it. Ha! The same thing with Linux/Unix. Five years ago, I marginally used it, and swore off it after having it heavily 10 years before. Two weeks ago, I found a meteor analysis program written in C and to uncover it was of use have (temporarily) climbed back on Linux. I manged to get a clunky old PC back that I gave a friend 3 years ago to put RH on. He had since gone on to a laptop, and put the PC in his garage. Just can't shake the computer habit. :-) Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor -- Wayne Watson (Watson Adventures, Prop., Nevada City, CA) (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time) In mathematics you don't understand things. You just get used to them. -- John Von Neumann (P.S. The same is true in life.) Web Page: www.speckledwithstars.net/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
Wayne Watson sierra_mtnv...@sbcglobal.net wrote Yep, when I bowed of programming long ago, I had Ousterhout's (something like that) book, and finally sold it on Amazom 5 years ago It was a good book in its day but is now well overdue an update. The book I'd recommend getting is Tcl/Tk in a Nutshell from O'Reilly Its only a reference but it covers Tk and Tix. There is hardly any Python docs for Tix although it is now part of the standard library. (Actually I think Tkinter needs an update too, there seem to be quite a few new Tk widgets that are not available in Tkinter... or is it just that they are not documented? I must have a poke around in v2.5... But the Nutshell seems to cover all the stuff that is in Tkinter) You can get a used Nutshell for around $6 via Amazon (and it covers expect too should you ever dabble with pyExpect). [ But note: for serious Tcl users the best book is Welsh's offering the Niutshell is just a reference that translates fairly easily to Tkinter/Tix] On Linux, I started using it in 1993 with RedHat 2 and Slackware 3. I dropped out for a spell then came back to it around Slackware 7 and Mandrake (now Mandriva) 3? But then I bought a Mac iBook and discovered cygwin and my current Linux box (Suse 9?) is lying idle. It only gets booted when I want to test some web things because it runs apache and Turbo Gears. Although I do now have an Asus Eee mini laptop with Linux and I'm using that to do some stuff now and then. Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
Alan Gauld alan.ga...@btinternet.com wrote Yep, when I bowed of programming long ago, I had Ousterhout's It was a good book in its day but is now well overdue an update. And lo and behold, listed on Amazon is the 2nd edition due in August 2009! How's that for service :-) BTW I also noticed that there is also now an O'Reilly pocket reference which might be even more useful to Python Tkinter users than the Nutshell - smaller and cheaper and even more terse! Although it doesn't appear to cover Tix... Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
Sounds like the O'Reilly book might be worth it. I have an interlibrary loan request out for a highly recommended Tk/Tcl book. I tried Cygwin about 5 years ago, and it just didn't cut it. Odd problems. It may be worth a shot again when I can free up some time. Alan Gauld wrote: "Wayne Watson" sierra_mtnv...@sbcglobal.net wrote Yep, when I bowed of programming long ago, I had Ousterhout's (something like that) book, and finally sold it on Amazom 5 years ago It was a good book in its day but is now well overdue an update. The book I'd recommend getting is Tcl/Tk in a Nutshell from O'Reilly Its only a reference but it covers Tk and Tix. There is hardly any Python docs for Tix although it is now part of the standard library. (Actually I think Tkinter needs an update too, there seem to be quite a few new Tk widgets that are not available in Tkinter... or is it just that they are not documented? I must have a poke around in v2.5... But the Nutshell seems to cover all the stuff that is in Tkinter) You can get a used Nutshell for around $6 via Amazon (and it covers expect too should you ever dabble with pyExpect). [ But note: for serious Tcl users the best book is Welsh's offering the Niutshell is just a reference that translates fairly easily to Tkinter/Tix] On Linux, I started using it in 1993 with RedHat 2 and Slackware 3. I dropped out for a spell then came back to it around Slackware 7 and Mandrake (now Mandriva) 3? But then I bought a Mac iBook and discovered cygwin and my current Linux box (Suse 9?) is lying idle. It only gets booted when I want to test some web things because it runs apache and Turbo Gears. Although I do now have an Asus Eee mini laptop with Linux and I'm using that to do some stuff now and then. Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor -- Signature.html Wayne Watson (Watson Adventures, Prop., Nevada City, CA) (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time) In mathematics you don't understand things. You just get used to them. -- John Von Neumann (P.S. The same is true in life.) Web Page: www.speckledwithstars.net/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
Alan Gauld alan.ga...@btinternet.com wrote I think Tkinter needs an update too, there seem to be quite a few new Tk widgets that are not available in Tkinter... or is it just that they are not documented? I must have a poke around in v2.5... I spoke too soon, its just the documentation needs an update the newer widgets are supported - at least paned window and Spinbox are, I didn't try any others. But you will need to look in the Tcl/Tk docs to find out how to use them! Here is the best site I know. It doesn't give Tkinter examples but does give Perl examples, which are pretty similar in style. http://www.tkdocs.com/tutorial/morewidgets.htm It also looks like we will get the new themed widgets in Python 2.7 and 3.1 which means Tkinter will no longer be the ugly duckling of Python GUI toolkits! Hooray! :-) HTH, -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/l2p/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
Wayne Watson sierra_mtnv...@sbcglobal.net wrote Can you easily construct a simple example where they are absolutely necessary, or at least provide a situation where they are necessary? I don't think you can. They are a convenience feature not a necessity. But the same can be said of standard dialogs, message boxes etc. You could build all of those from basic widgets but it woulfd be a pain. Sometimes Control variables save you some pain. Personally I don't bother with them much but others like them. Alan G ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
Title: Signature.html I have no idea of the history of these variables, but they have very limited descriptions and examples. Maybe someone like Grayson goes into detail on them. Looking at the program I'm concerned about, it almost looks like the use is a learned response to dealing with the widgets used. That's OK. I just wanted to make sure I wasn't overlooking something. It provided a helpful interlude. :-) Alan Gauld wrote: "Wayne Watson" sierra_mtnv...@sbcglobal.net wrote Can you easily construct a simple example where they are absolutely necessary, or at least provide a situation where they are necessary? I don't think you can. They are a convenience feature not a necessity. But the same can be said of standard dialogs, message boxes etc. You could build all of those from basic widgets but it woulfd be a pain. Sometimes Control variables save you some pain. Personally I don't bother with them much but others like them. Alan G ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor -- Wayne Watson (Watson Adventures, Prop., Nevada City, CA) (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time) In mathematics you don't understand things. You just get used to them. -- John Von Neumann (P.S. The same is true in life.) Web Page: www.speckledwithstars.net/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
Title: Signature.html Another thought occurred to me about this situation. Suppose I have a dialog with two Entry objects in a dialog object called TwoEntries: entry1 = Entry(master, width=10).grid(row=4, column=1) entry2 = Entry(master, width=10).grid(row=5, column=1) and I do not use a StringVar to return the values entered. Is it possible to reach inside TwoEntries, after returning from it, and grab entry1 and 2? It would seem so if the call was dialog=TwoEntries(...). Wayne Watson wrote: I have no idea of the history of these variables, but they have very limited descriptions and examples. Maybe someone like Grayson goes into detail on them. Looking at the program I'm concerned about, it almost looks like the use is a learned response to dealing with the widgets used. That's OK. I just wanted to make sure I wasn't overlooking something. It provided a helpful interlude. :-) Alan Gauld wrote: "Wayne Watson" sierra_mtnv...@sbcglobal.net wrote Can you easily construct a simple example where they are absolutely necessary, or at least provide a situation where they are necessary? I don't think you can. They are a convenience feature not a necessity. But the same can be said of standard dialogs, message boxes etc. You could build all of those from basic widgets but it woulfd be a pain. Sometimes Control variables save you some pain. Personally I don't bother with them much but others like them. Alan G ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor -- Wayne Watson (Watson Adventures, Prop., Nevada City, CA) (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time) In mathematics you don't understand things. You just get used to them. -- John Von Neumann (P.S. The same is true in life.) Web Page: www.speckledwithstars.net/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor -- Signature.html Wayne Watson (Watson Adventures, Prop., Nevada City, CA) (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time) In mathematics you don't understand things. You just get used to them. -- John Von Neumann (P.S. The same is true in life.) Web Page: www.speckledwithstars.net/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
Wayne Watson sierra_mtnv...@sbcglobal.net wrote Apparently Entry does not have a callback. Thats the magic of Control Variables. They automatically get populated when the user enters data into the Entry widget. But since Entry widgets are usually part if a form and there will be several of them its more useful to wait for the whole form to be complteed and then hit a Submit button. The button handler can then read all of the Entry fields using get() So you are right that there is no callback per se except for the auto settigh of control variables, but you can't trigger an action based on that. However you can of course bind an event to the Entry box such as keypress, mouse over etc. and the event can trigger an action, so in your example you could bind a carriage return keystroke to some action. See the event handling topic in my tutorial for an example of binding a specific key to an event. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
On Thu, Mar 5, 2009 at 10:52 PM, Wayne Watson
sierra_mtnv...@sbcglobal.net wrote:
Apparently Entry does not have a callback. It seems as though it should. If
one enters data into it and presses Return, then it would be good to know
what the data is, so it can be used elsewhere. However, that's not the way
it works. One seems to need a button or some other widget to make it
happen*. So what's the game with it?
You can bind a Return event to an Entry widget. Here is a simple example:
from Tkinter import *
def showText(evt):
print 'Text is:', text.get('0.0', END)
return 'break' # Prevent the event from propagating to the Text widget
root = Tk()
text = Text()
# This line binds the showText handler to the Return key event
text.bind('Return', showText)
text.pack()
root.mainloop()
Kent
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Re: [Tutor] Misunderstanding the Entry Widget
Title: Signature.html Control variables. What is the difference between IntVar, BooleanVar, StringVar, and DoubleVar? For example, in the program below, it looks like I get the same result usint IntVar or StringVar. It almost appears the usage depends on what widget one uses: Entry, RadioButton, CheckBox, ... ===begin= from Tkinter import * # Use of control variables def mycallback(): print "User entered:" , e.get() print "Operationg by 2 gives: ", e.get()*2 master = Tk() v=StringVar() #v=IntVar() print v,type(v) e = Entry(master,textvariable=v) e.pack() b = Button(master, text="Push to Print", width=10, command=mycallback) b.pack() e.focus_set() v.set(123) mainloop() =End= Alan Gauld wrote: "Wayne Watson" sierra_mtnv...@sbcglobal.net wrote Apparently Entry does not have a callback. Thats the magic of Control Variables. They automatically get populated when the user enters data into the Entry widget. But since Entry widgets are usually part if a form and there will be several of them its more useful to wait for the whole form to be complteed and then hit a Submit button. The button handler can then read all of the Entry fields using get() So you are right that there is no callback per se except for the auto settigh of control variables, but you can't trigger an action based on that. However you can of course bind an event to the Entry box such as keypress, mouse over etc. and the event can trigger an action, so in your example you could bind a carriage return keystroke to some action. See the event handling topic in my tutorial for an example of binding a specific key to an event. -- Wayne Watson (Watson Adventures, Prop., Nevada City, CA) (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time) In mathematics you don't understand things. You just get used to them. -- John Von Neumann (P.S. The same is true in life.) Web Page: www.speckledwithstars.net/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
On Fri, Mar 6, 2009 at 7:15 AM, Wayne Watson sierra_mtnv...@sbcglobal.net wrote: Control variables. What is the difference between IntVar, BooleanVar, StringVar, and DoubleVar? The difference is the type of value returned by get(). For example, in the program below, it looks like I get the same result usint IntVar or StringVar. It almost appears the usage depends on what widget one uses: Entry, RadioButton, CheckBox, ... ===begin= from Tkinter import * # Use of control variables def mycallback(): print User entered: , e.get() print Operationg by 2 gives: , e.get()*2 Change the above to use v.get(). e.get() has nothing to do with the var. master = Tk() v=StringVar() #v=IntVar() print v,type(v) Try this: print v, type(v), type(v.get()) Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
I've just got to stop using one letter for variables, especially ones that sound alike! :-) Other than v tracking every value change made, did I gain anything by using it? It seems to me that control variables are of marginal use. I might have thought they were necessary for use with scale widgets, but I'm looking at an example that says otherwise. Can you easily construct a simple example where they are absolutely necessary, or at least provide a situation where they are necessary? Kent Johnson wrote: On Fri, Mar 6, 2009 at 7:15 AM, Wayne Watson sierra_mtnv...@sbcglobal.net wrote: Control variables. What is the difference between IntVar, BooleanVar, StringVar, and DoubleVar? The difference is the type of value returned by get(). For example, in the program below, it looks like I get the same result usint IntVar or StringVar. It almost appears the usage depends on what widget one uses: Entry, RadioButton, CheckBox, ... ===begin= from Tkinter import * # Use of control variables def mycallback(): print "User entered:" , e.get() print "Operationg by 2 gives: ", e.get()*2 Change the above to use v.get(). e.get() has nothing to do with the var. master = Tk() v=StringVar() #v=IntVar() print v,type(v) Try this: print v, type(v), type(v.get()) Kent -- Signature.html Wayne Watson (Watson Adventures, Prop., Nevada City, CA) (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time) In mathematics you don't understand things. You just get used to them. -- John Von Neumann (P.S. The same is true in life.) Web Page: www.speckledwithstars.net/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misunderstanding the Entry Widget
On Fri, Mar 6, 2009 at 11:26 AM, Wayne Watson sierra_mtnv...@sbcglobal.net wrote: I've just got to stop using one letter for variables, especially ones that sound alike! :-) Other than v tracking every value change made, did I gain anything by using it? It seems to me that control variables are of marginal use. I might have thought they were necessary for use with scale widgets, but I'm looking at an example that says otherwise. Can you easily construct a simple example where they are absolutely necessary, or at least provide a situation where they are necessary? You need a variable to get the state of a Checkbutton. Variables would be helpful if you had multiple controls displaying the same value. They might give a useful decoupling between the GUI and other clients of the data; they are a mini-model, in the Model-View-Controller sense. Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Misunderstanding the Entry Widget
Title: Signature.html Apparently Entry does not have a callback. It seems as though it should. If one enters data into it and presses Return, then it would be good to know what the data is, so it can be used elsewhere. However, that's not the way it works. One seems to need a button or some other widget to make it happen*. So what's the game with it? * I have looked at 3 Entry examples on the web that appear to be well written, and none of them really return anything, although they supposedly should print the entry data once their button is pressed. Well, OK, one does, but only after I had to remove the dash from the name and replace it with an underscore. Whoops, that one doesn't really work either. -- Wayne Watson (Watson Adventures, Prop., Nevada City, CA) (121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time) In mathematics you don't understand things. You just get used to them. -- John Von Neumann (P.S. The same is true in life.) Web Page: www.speckledwithstars.net/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
