I came across a problem that probably has a simple, clever, answer -- but it is eluding me. I was trying to create a set of tab buttons on a Tkinter page using Buttons. These are created dynamically when the user loads a file. I don't know in advance how many files will get opened, so I want to have a variable number of tabs.
So we have a Frame T; and an array of tabs XT[]; and a function switch_tabs(n) that will handle the details of switching the data base, titles, etc. I compute the tab number: Whoopsie = len(XT) And I create a new Button: XT.append(Button(T,text="Viola:New Tab",command=lambda: switch_tabs(whoopsie)) It all works fine except for this one minor detail. Whoopsie can't be a constant because I don't know in advance what constant to use. And if whoopsie is a variable, it apparently is evaluated at execution time, and will have the then current value of whoopsie, not the value I wanted to set at creation time. I tried everything I could think of including copy.copy(whoopsie) to get a constant set so that switch_tabs could know which tab to switch to. Couldn't do it. I was starting to look at tracing back through stack frames when it came to me that RadioButtons unlike generic Buttons have a variable-value attribute pair that behaves as I desire. So this manifestation of the problem is worked around. But I expect that I'll see this problem again in some other guise. Am I missing something? Probably something simple? What? -- View this message in context: http://www.nabble.com/How-to-set-a-constant-in-lambda-tp21689312p21689312.html Sent from the Python - tkinter-discuss mailing list archive at Nabble.com. _______________________________________________ Tkinter-discuss mailing list Tkinter-discuss@python.org http://mail.python.org/mailman/listinfo/tkinter-discuss
