Re: [Tutor] how to change the command "string" on a tkinter Button?
On 01/07/18 02:17, Alan Gauld via Tutor wrote:
On 30/06/18 03:55, Chris Roy-Smith wrote:
I am trying to change the command of a tkinter Button in my program.
Eventually I want to be able to do this to many buttons.
Since I'm not 100% sure if you mean the command or the label or both
here is a simple example that does both...
import tkinter as tk
def cmd1(): print('This is command 1')
def cmd2(): print('This is number 2')
def swapCmd():
c = b1['command']
# kluge to get the function name from Tcl id
if str(c).endswith("cmd1"):
b1['command'] = cmd2
else:
b1['command'] = cmd1
def swapText():
t = b1['text']
if t == "Cool":
b1['text'] = "Hot"
else:
b1['text'] = "Cool"
# make GUI
top = tk.Tk()
win = tk.Frame(top)
win.pack()
b1 = tk.Button(win,text="Cool", command=cmd1)
b1.pack()
b2 = tk.Button(win, text="Swap text", command=swapText)
b2.pack()
b3 = tk.Button(win, text="Swap cmd", command=swapCmd)
b3.pack()
top.mainloop()
###
Thank you Alan, you have covered what I think I wanted to achieve. For
me, programming is a continual learning experience, unfortunately I seem
to forget nearly as much as I learn, Python is the first language I have
attempted since macro assembler for CP/M. Python seems to be another world.
It appears that I broke the code I started experimenting with, to try
changing the command, and that may have added to my confusion.
I'll play with your example to try an understand what is going on.
Regards, Chris Roy-Smith
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Re: [Tutor] how to change the command "string" on a tkinter Button?
On Sun, Jul 01, 2018 at 03:32:59PM +1000, Chris Roy-Smith wrote: > Python is the first language I have > attempted since macro assembler for CP/M. Python seems to be another world. Yes indeed, high-level languages like Python *are* a radically different programming experience than low-level languages like assembler. The fundamental execution and data models of the languages are *very* different: - assembler lives in a universe of bytes and words; there are few abstractions and you are dealing (very nearly) with the lowest level of flipping bits in hardware, or at least of moving bytes. - Python lives in a world of big, complex abstractions like dicts and Unicode text and even objects as complex as "web server", and the fundamental operations are multiple layers away from moving bytes. It's not surprising that this may require some re-adjustment of your mental model of how to program. > It appears that I broke the code I started experimenting with, to try > changing the command, and that may have added to my confusion. "Save As..." before engaging in big changes is your friend :-) Even better would be to learn a form of VCS (version control system) such as Mercurial (hg) or git. Depending on the text editor you are using, it may have VCS integration available. Off-topic: I see you are a fellow Internode user, like me. Which part of Australia are you in, and is your internet connection giving you as much grief as mine is? I'm pretty sure that Internode is *grossly* oversubscribed. E.g. when I try doing a google search, I'll usually get "Waiting for www.google.com..." which then times out about six or twelve times on average before succeeding to connect, after which it is damn near instantaneous. I downloaded 2 GB of data in about ten minutes yesterday, not long followed by a 2K email that took *three hours* to leave my computer because the connection to Internode's mail server kept timing out. -- Steve ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] how to change the command "string" on a tkinter Button?
On 01/07/18 02:17, Alan Gauld via Tutor wrote:
On 30/06/18 03:55, Chris Roy-Smith wrote:
I am trying to change the command of a tkinter Button in my program.
Eventually I want to be able to do this to many buttons.
Since I'm not 100% sure if you mean the command or the label or both
here is a simple example that does both...
import tkinter as tk
def cmd1(): print('This is command 1')
def cmd2(): print('This is number 2')
I was hoping eventually to generate the command form the results of a
database query, not knowing the exact command until run time. Perhaps
what I was trying to achieve is too close to self modifying code, I was
warned off this when I used to dabble in assembler. Does the same advice
hold for python?
def swapCmd():
c = b1['command']
# kluge to get the function name from Tcl id
if str(c).endswith("cmd1"):
b1['command'] = cmd2
else:
b1['command'] = cmd1
I never thought to try anything like this, I was thinking more along the
lines for how to change the text of a Labe.l
def swapText():
t = b1['text']
if t == "Cool":
b1['text'] = "Hot"
else:
b1['text'] = "Cool"
# make GUI
top = tk.Tk()
win = tk.Frame(top)
win.pack()
b1 = tk.Button(win,text="Cool", command=cmd1)
b1.pack()
b2 = tk.Button(win, text="Swap text", command=swapText)
b2.pack()
b3 = tk.Button(win, text="Swap cmd", command=swapCmd)
b3.pack()
top.mainloop()
###
Thank you again Alan,
While your solution works, it's not how I imagined in terms of approach.
Eventually I wanted to change the command of a variable number of
buttons with the actual command depending on the results of a database
query. I am unable to see how I can manage this in your solution style (
predetermined commands) might be difficult to achieve ( with my limited
programming skills ). Your solution made me rethink what I was
attempting to do, and found with a slightly modified database query, I
didn't need to change the command at all. The rest of this bit of
program I have already solved.
Now I just have to learn a lot more about classes, and objects.
again, thank you Alan.
Regards, Chris Roy-Smith
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Re: [Tutor] RAD GUI Development (like Visual Studio/VBA)
On 30/06/2018 19:21, Alan Gauld via Tutor wrote: > On 30/06/18 11:50, Shall, Sydney wrote: > >>> And if you want to try using Jython or MacPython(?) >>> you can use the native GUI builders for those: >>> - Eclipse/Netbeans (Java) >>> - XDeveloper (MacOS) - I tried this once and it kind of works... >>> >> Alan, >> >> Could you expand a bit on the use of XDeveloper. >> I have need of some such utility for my project and I use a MAC OS X. > I've only gone through the tutorial and made some tweaks > to the resulting code but it seemed to work pretty much > as usual for Cocoa projects using Objective C. > > You layout the UI then connect the widgets to your code > (which is in Python of course). > > The PyObjC project is here: > > https://pythonhosted.org/pyobjc/ > > The tutorial I used is here: > > https://pythonhosted.org/pyobjc/tutorials/firstapp.html > > Note that it is old, but I only have an iBook from 2001 > running MacOS Lion, so age wasn't an issue for me! > Thank you. I shall spend some time studying the two sites and see what I can make of it. Sydney _ Professor Sydney Shall Department of Haematology/Oncology Phone: +(0)2078489200 E-Mail: sydney.shall [Correspondents outside the College should add @kcl.ac.uk] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] how to change the command "string" on a tkinter Button?
On 01/07/18 19:19, Steven D'Aprano wrote: On Sun, Jul 01, 2018 at 03:32:59PM +1000, Chris Roy-Smith wrote: Python is the first language I have attempted since macro assembler for CP/M. Python seems to be another world. Yes indeed, high-level languages like Python *are* a radically different programming experience than low-level languages like assembler. The fundamental execution and data models of the languages are *very* different: - assembler lives in a universe of bytes and words; there are few abstractions and you are dealing (very nearly) with the lowest level of flipping bits in hardware, or at least of moving bytes. - Python lives in a world of big, complex abstractions like dicts and Unicode text and even objects as complex as "web server", and the fundamental operations are multiple layers away from moving bytes. It's not surprising that this may require some re-adjustment of your mental model of how to program. those big complex bits cut down on the amount of code needed to achieve a given task. :-) It appears that I broke the code I started experimenting with, to try changing the command, and that may have added to my confusion. "Save As..." before engaging in big changes is your friend :-) yes, was supposed to be a quick experiment to test idea ;) Even better would be to learn a form of VCS (version control system) such as Mercurial (hg) or git. Depending on the text editor you are using, it may have VCS integration available. I don't know anything about these tools, I use Kate as my editor for my programming. I usually give a new number to separate versions, I'm sure there are better ways, I just haven't gone looking for them yet. Idle only looks useful for CLI stuff. Off-topic: I see you are a fellow Internode user, like me. Which part of Australia are you in, and is your internet connection giving you as much grief as mine is? I have had little trouble with Internode over the last 13 years or so. The other day is the first time I had a really slow download, went to another mirror in Western Australia, and all went as fast as I'm supposed to get (I have the slowest option of NBN, ( bronze 100) which I have never NEEDED extra bandwidth, it might be nice, but I don't use the sort of service which depends on good bandwidth, downloads can go all night for all I care). I'm not greedy though it's all very fast compared to dial up, or packet radio I'm pretty sure that Internode is *grossly* oversubscribed. E.g. when I try doing a google search, I'll usually get "Waiting for www.google.com..." which then times out about six or twelve times on average before succeeding to connect, after which it is damn near instantaneous. I search with DuckDuckGo, and rarely have any response issue with my searches. I don't think they sell my search data. I downloaded 2 GB of data in about ten minutes yesterday, not long followed by a 2K email that took *three hours* to leave my computer because the connection to Internode's mail server kept timing out. Your connection is a bit faster than mine. I've not experienced any speed issues with the email server. Regards, Chris Roy-Smith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] how to change the command "string" on a tkinter Button?
On 01/07/18 09:15, Chris Roy-Smith wrote:
>> def cmd2(): print('This is number 2')
> I was hoping eventually to generate the command form the results of a
> database query, not knowing the exact command until run time. Perhaps
> what I was trying to achieve is too close to self modifying code, I was
> warned off this when I used to dabble in assembler. Does the same advice
> hold for python?
writing sel;f modifying code is so difficult to get right and
so easy to be catastrophically wrong that its best avoided
in any language. Even guru level programmers get that stuff
wrong.
But it sounds like you probably want data driven code which
is (still tricky but) a lot easier. Tell us more with some
examples of the data and we can probably help.
> While your solution works, it's not how I imagined in terms of approach.
> Eventually I wanted to change the command of a variable number of
> buttons with the actual command depending on the results of a database
> query.
Sure, but the actual changing of the command will
still look like my code I suspect.
The tricky bit is creating the appropriate function
object so that you can assign it,.
The number of widgets is just a matter of a list
and an iterator
And remember, in a GUI everyting is event driven so you need to think
about what event will trigger this reassignment of commands.
You need the GUI in place and some kind of event catcher
(button?, timer?) to handle the changeover.
> attempting to do, and found with a slightly modified database query, I
> didn't need to change the command at all. The rest of this bit of
> program I have already solved.
> Now I just have to learn a lot more about classes, and objects.
OK, Glad you avoided the tricky stiff. Its very rarely needed.
--
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] how to change the command "string" on a tkinter Button?
On 01/07/18 11:33, Chris Roy-Smith wrote: >> Even better would be to learn a form of VCS (version control system) > I don't know anything about these tools, VCS store versions of a file. You can check for differences between versions, restore previous versions, even merge different versions. Modst also allow you to freeze a collection of file versions for a release so that you can restore a previous version of your project. They are what all professional programmers use on big projects. One of the oldest and simplest VCS tools is RCS (Revision Control System). It basically has 2 commands: ci - checkin a file. co - check out a version. So you create a file and get it working. Create a folder in your project folder called RCS Check it in and keep a copy for editing ci -l myfile.py Now make changes until you have a new version check it in ci -l myfile.py Realize that you made a mistake, get the original version back co -l -v1.1 myfile.py and so on. At each check in the system will ask you to describe your changes There are other commands you can use to query the versions etc. The system only stores the differences between versions so doesn't use a huge amount of storage. https://www.gnu.org/software/rcs/ More recent systems work on servers across a network and tend to operate at the project/folder level rather than individual files, but the basic ideas remain the same. Steven mentioned Mercurial and Git, there is also Subversion(SVN) and CVS(based on RCS and by the same team). There are also commercial tools, some costing up to $1000 per seat! Its big business. One of the best is ClearCase (now owned by IBM?), nearly magical in its capabilities but very expensive! Some editors will have menu commands to automatically do the check in/out operations for you once you configure the tool and paths in the properties. > I use Kate as my editor Perfectly fine tool, no need to change unless you want to. > ...Idle only looks useful for CLI stuff. Not at all it has a full file editor and integrated interpreter so you can save your file and hit F5 to run the code with the output in the "shell window" (which is what appears at startup) Even better is IDLEX which has a lot of extra features such as tabbed editing windows, code folding, line numbering, intelligent paste from the shell, etc etc... Many IDLEX features are planned for future IDLE releases, but the approval process takes time. Meanwhile IDLEX is available here: http://idlex.sourceforge.net/features.html And all written in Python/Tkinter so a great place to learn Tkinter tricks! -- 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
