I would like to make a Button that assign a new variable with a value in a compact form.
I tried this:
def whichButton(self, _var, _pressedButton):
self._var = _pressedButton
def checkScooter(self):
self.checkScooter = Button(window, text="Standard", command=lambda: self.whichButton(edition, 1))
self.checkScooter(row=1, column=0)
def checkAbonnement(self):
self.checkAbonnement = Button(window, text="Gold", command=lambda: self.whichButton(abonnement, 3))
self.checkAbonnement(row=1, column=0)
It just gives me an error, that "edition" is not defined, but I want the Button to define it
Any tips?
Your request to set a new variable is odd, and probably not the right solution to whatever problem you're trying to solve.
That being said, you can use setattr to set the value based on the name of a variable. That variable doesn't have to exist. For example, to set the variable self.edition to 1 you can do setattr(self, "edition", 1).
Therefore, you can pass in the string name of the variable to your whichButton function, and use setattr to set a variable with that name.
It would look something like this:
def whichButton(self, _var, _pressedButton):
setattr(self, _var, _pressedButton)
...
self.checkScooter = Button(..., command=lambda: self.whichButton("edition", 1))
...
self.checkAbonnement = Button(..., command=lambda: self.whichButton("abonnement", 3))
In the above code, clicking either button will either set self.edition or self.abonnement.
There is almost certainly a better solution to your problem, but your question doesn't provide any details about what problem you're really trying to solve. A simple mprovement over this would be to use a dictionary to hold your "new" variables rather than creating literally new variables.
You can do that by defining a dictionary in your __init__ and then setting it in your whichButton function.
It would look something like this:
class Something:
def __init__(self):
self._vars = {}
def whichButton(self, name, new_value):
self._vars[name] = new_value
This has the advantage that all of these special variables exist in a single data structure, separate from the object. That means that it would be impossible to accidentally overwrite instance variables.
Related
I'm currently creating a GUI in order to turn a lot of individual instruments into one complete system. In def smuSelect(self) I create a list self.smuChoices I can use to call individual choices such as smuChoices[0] and it will return "2410(1)".
Once I call def checkBoxSetup it returns PY_VARxxx. I've tried searching the different forums and everything. I've seen mentions using the .get() which just gives me the state of the individual choice. The reason I want the actual string itself is I would like to use it in def testSetup(self) for the user to assign specific names to the individual machine, for example, 2410 = Gate.
My initial attempt was to create another variable smuChoice2 but I believe this is still changing the original list self.smuChoices.
import tkinter as tk
import numpy as np
from tkinter import ttk
def checkBoxSetup(smuChoice2): #TK.INTVAR() IS CHANGING NAME OF SMUS NEED TO CREATE ANOTHER INSTANCE OF SELF.SMUCHOICES
for val, SMU in enumerate(smuChoice2):
smuChoice2[val] = tk.IntVar()
b = tk.Checkbutton(smuSelection,text=SMU,variable=smuChoice2[val])
b.grid()
root = tk.Tk()
root.title("SMU Selection")
"""
Selects the specific SMUs that are going to be used, only allow amount up to chosen terminals.
--> If only allow 590 if CV is picked, also only allow use of low voltage SMU (maybe dim options that aren't available)
--> Clear Checkboxes once complete
--> change checkbox selection method
"""
smuChoices = [
"2410(1)",
"2410(2)",
"6430",
"590 (CV)",
"2400",
"2420"
]
smuChoice2 = smuChoices
smuSelection = ttk.Frame(root)
selectInstruct = tk.Label(smuSelection,text="Choose SMUs").grid()
print(smuChoices[0]) #Accessing list prior to checkboxsetup resulting in 2410(1)
checkBoxSetup(smuChoice2)
print(smuChoices[0]) #Accessing list after check box setup resulting in PY_VAR376
variableSMUs = tk.StringVar()
w7_Button = tk.Button(smuSelection,text="Enter").grid()
w8_Button = tk.Button(smuSelection,text="Setup Window").grid()
root.mainloop()
I was able to solve the problem by changing my list, smuChoices, to a dictionary then modifying
def checkBoxSetup(smuChoice2):
for val, SMU in enumerate(smuChoice2):
smuChoice2[val] = tk.IntVar()
b = tk.Checkbutton(smuSelection,text=SMU,variable=smuChoice2[val])
b.grid()
to
def checkBoxSetup(self):
for i in self.smuChoices:
self.smuChoices[i] = tk.IntVar()
b = tk.Checkbutton(self.smuSelection,text=i,variable=self.smuChoices[i])
b.grid()
Previously I was replacing the variable with what I'm guessing is some identifier that tkinter uses to store the state which is why I was getting PYxxx.
First of all getting PY_VARXX instead of what's in a variable class indicates the lack of get().
replace:
print(self.smuChoices[0])
with:
print(self.smuChoices[0].get())
Secondly, if you want to display the value of a variable class on a label, button, etc. you could rather just use the textvariable option by simply assigning the variable class to it.
Replace:
tk.Label(self.smuName,text=SMU).grid()
with:
tk.Label(self.smuName, textvariable=self.smuChoices[val]).grid()
Your question is still a bit unclear to me but I will try to provide an answer to the best of my understanding.
As I understand it, you're trying to create a set of Checkbuttons for a given list of items. Below is an example of a method that takes items as an argument and returns a dictionary of checkboxes that have root as their parent:
import tkinter as tk
def dict_of_cbs(iterable, parent):
if iterable:
dict_of_cbs = dict()
for item in iterable:
dict_of_cbs[item] = tk.Checkbutton(parent)
dict_of_cbs[item]['text'] = item
dict_of_cbs[item].pack() # it's probably a better idea to manage
# geometry in the same place wherever
# the parent is customizing its
# children's layout
return dict_of_cbs
if __name__ == '__main__':
root = tk.Tk()
items = ("These", "are", "some", "items.")
my_checkboxes = dict_of_cbs(items, root)
root.mainloop()
Additionally note that I haven't used any variable classes (BooleanVar, DoubleVar, IntVar or StringVar) as they seem to be redundant in this particular case.
This comes from a button that when pressed generates a radiobutton. I am not able to access to the choice made with radiobutton. Everything works fine, but the output of selected function is zero. I try using both local and global var but the result is the same.
def callback_st(): # RadioButton select technology
var = IntVar()
m=0
for m in range(len(un_tech)):
Radiobutton(radio_frame, text=un_tech[m], value=m, variable=var,
command=selected(var)).pack(anchor=W)
def selected(var):
print(var)
This doesn't work. I solved using lambda:
def selected(jst):
global sel_technology
sel_technology=un_tech[jst]
print(sel_technology)
def callback_st(): #RadioButton select technology
var_st = IntVar()
m=0
for m in range(len(un_tech)):
Radiobutton(radio_frame, text=un_tech[m], value=m, variable=var_st,
command = lambda jst=m: selected(jst)).pack(anchor=W)
This works as i want, but it isn't the solution that i want and i think is not the correct way. So, somebody can help me to find the right way?
In your first try, you call selected immediately, when var has a value of 0. You avoided this with the lambda expression, but you are correct that this is an awkward workaround for the original mistake. Make var global and have selected access it as a global. Modifying your first code:
var = IntVar()
def selected():
print(var.get())
def callback_st():
...
...command=selected...
If you were defining a class and methods, var would be an instance attribute instead of global.
The idea of this code is, the user presses the first button and enters what they want, then they press the second button and it prints it out. Can someone please tell me why my return statement is not working? It says that 'variable' is not defined. Thanks in advance for taking the time to read my question.
from tkinter import*
def fun():
variable = input('Enter Here:')
return variable
def fun_2():
print(variable)
window = Tk()
button = Button(text = 'Button', command = fun )
button2 = Button(text = 'Button2', command = fun_2 )
button.pack()
button2.pack()
window.mainloop()
In python when you create a variable inside of a function, it is only defined within that function. Therefore other functions will not be able to see it.
In this case, you will probably want some shared state within an object. Something like:
class MyClass:
def fun(self):
self.variable = input('Enter Here:')
def fun_2(self):
print(self.variable)
mc = MyClass()
window = Tk()
button = Button(text = 'Button', command = mc.fun )
button2 = Button(text = 'Button2', command = mc.fun_2 )
button.pack()
button2.pack()
fun() may return a value, but Tkinter buttons don't do anything with that return value.
Note that I used the phrase return a value, not return a variable. The return statement passes back the value of an expression, not the variable variable here. As such, the variable variable is not made into a global that other functions then can access.
Here, you can make variable a global, and tell fun to set that global:
variable = 'No value set just yet'
def fun():
global variable
variable = input('Enter Here:')
Since you did use any assignment in fun2, variable there is already looked up as a global, and it'll now successfully print the value of variable since it now can find that name.
The problem is in in fun2(). It does not get variable as an input parameter.
def fun_2(variable):
print(variable)
But note that you have to call fun_2 now with the appropriate argument. Also, as the function stands right now, there is little point in having the function if you just do a print inside of it.
Take away message: variable is not global in Python, and as such you must pass it to each function that wants to use it.
I am working on an application that is supposed to support both running from a console and from a GUI. The application has several options to choose from, and since in both running modes the program is going to have the same options obviously, I made a generalisation:
class Option:
def __init__(self, par_name, par_desc):
self.name = par_name
self.desc = par_desc
class Mode():
def __init__(self):
self.options = []
self.options.append(Option('Option1', 'Desc1'))
self.options.append(Option('Option2', 'Desc2'))
self.options.append(Option('Option3', 'Desc3'))
self.options.append(Option('Option4', 'Desc4'))
self.options.append(Option('Option5', 'Desc5'))
#And so on
The problem is that in GUI, those options are going to be buttons, so I have to add a new field to an Option class and I'm doing it like this:
def onMouseEnter(par_event, par_option):
helpLabel.configure(text = par_option.desc)
return
def onMouseLeave(par_event):
helpLabel.configure(text = '')
return
class GUIMode(Mode):
#...
for iOption in self.options:
iOption.button = Button(wrapper, text = iOption.name, bg = '#004A7F', fg = 'white')
iOption.button.bind('<Enter>', lambda par_event: onMouseEnter(par_event, iOption))
iOption.button.bind('<Leave>', lambda par_event: onMouseLeave(par_event))
#...
There is also a "help label" showing the description of the option every time a mouse hovers over it, so there I am binding those functions.
What is happening is that while I am indeed successfully adding a new field with a button, the bind function seems to mess up and the result is this:
Help label is always showing the description of the last option added, no matter over which button I hover. The problem seems to go away if I directly modify the Option class instead, like this:
class Option:
def __init__(self, par_name, par_desc):
self.name = par_name
self.desc = par_desc
self.button = Button(wrapper, text = self.name, bg = '#004A7F', fg = 'white')
self.button.bind('<Enter>', lambda par_event: onMouseEnter(par_event, self))
self.button.bind('<Leave>', lambda par_event: onMouseLeave(par_event))
But I obviously can't keep it that way because the console mode will get those fields too which I don't really want. Isn't this the same thing, however? Why does it matter if I do it in a constructor with self or in a loop later? I therefore assume that the problem might be in a way I dynamically add the field to the class?
Here is the full minimal and runnable test code or whatever it is called, if you want to mess with it: http://pastebin.com/0PWnF2P0
Thank you for your time
The problem is that the value of iOption is evaluated after the
for iOption in self.option:
loops are complete. Since you reset iOption on each iteration, when the loop is completed iOption has the same value, namely the last element in self.options. You can demonstrate this at-event-time binding with the snippet:
def debug_late_bind(event):
print(iOption)
onMouseEnter(event, iOption)
for iOption in self.options:
iOption.button = Button(wrapper, text = iOption.name,
bg = '#004A7F', fg = 'white')
iOption.button.bind('<Enter>', debug_late_bind)
which will show that all events that iOption has the same value.
I split out the use of iOption to debug_late_bind to show that iOption comes in from the class scope and is not evaluated when the bind() call is executed. A more simple example would be
def print_i():
print(i)
for i in range(5):
pass
print_i()
which prints "4" because that is the last value that was assigned to i. This is why every call in your code to onMouseEnter(par_event, iOption) has the same value for iOption; it is evaluated at the time of the event, not the time of the bind. I suggest that you read up on model view controller and understand how you've tangled the view and the controller. The primary reason this has happened is that you've got two views (console and tk) which should be less coupled with the model.
Extracting the .widget property of the event is a decent workaround, but better still would be to not overwrite the scalar iOption, but instead use list of individual buttons. The code
for n, iOption in enumerate(self.options):
would help in creating a list. In your proposed workaround, you are encoding too much of the iOption model in the tkinter view. That's bound to bite you again at some point.
I don't know what the actual problem was with my original code, but I kind of just bypassed it. I added a dictionary with button as a key and option as a value and I just used the par_event.widget to get the option and it's description, which is working fine:
buttonOption = {}
def onMouseEnter(par_event):
helpLabel.configure(text = buttonOption[par_event.widget].desc)
return
def onMouseLeave(par_event):
helpLabel.configure(text = '')
return
class GUIMode(Mode):
def run(self):
#...
for iOption in self.options:
iOption.button = Button(wrapper, text = iOption.name, bg = '#004A7F', fg = 'white')
iOption.button.bind('<Enter>', lambda par_event: onMouseEnter(par_event))
iOption.button.bind('<Leave>', lambda par_event: onMouseLeave(par_event))
buttonOption[iOption.button] = iOption
#...
I'm working on a GUI for a project in school. All the buttons that I have in my GUI are bound with functions that I have created. These functions call for already predefined functions. For some of the predefined functions, I need one or two arguments and I have solved that with entries. I type in the arguments in the right entries that are connected to the specific button and when I press the button, the function will run with the corresponding arguments.
The thing I want to do is to in some way when I press a button, the function should be saved to a list instead of being executed right away. And when I push the "run" button(a new button that I will create) everything in my list will be executed. I have been thinking about using a list box but I don't know exactly how they work or if its even possible to run a list box that contains a number of functions. Does someone have any ideas or solutions for me? Can I use the list box for this or is there something else that is better to use?
class App:
def __init__(self, master):
frame = Frame(master)
frame.pack()
self.entry1 = IntVar()
self.entry2 = IntVar()
def do_something():
value1 = self.entry1.get()
value2 = self.entry2.get()
self.listbox.insert(END, "predefined_function(value1, value2)")
def run_listbox_contents():
pass
self.button = Button(frame, text="Move", command=lambda: do_something())
self.button.pack(side=TOP)
self.entry1.set("value1")
self.entry = Entry(frame, textvariable=self.entry1)
self.entry.pack(side=TOP)
self.entry2.set("value2")
self.entry = Entry(frame, textvariable=self.entry2)
self.entry.pack(side=TOP)
self.listbox = Listbox(master)
self.listbox.pack(side=TOP)
root = Tk()
app = App(root)
root.title("Mindstorms GUI")
root.geometry("800x1200")
root.mainloop()
root.destroy()
Just use a standard list.
something like this
def hest(txt):
print "hest: " +txt
def horse(txt):
print "horse: " + txt
funcList = []
funcList.append(hest)
funcList.append(horse)
for x in funcList:
x("Wow")
This outputs
hest: Wow
horse: Wow
Was this what you wanted?
If I were you, I wouldn't want to save functions to a list. I would suggest another solution for you.
I suppose you have heard of the principle of MVC (Model-View-Controller). In your case, the list box is a part of view, and the process that saves functions and then calls them at once is a part of controller. Separate them.
You might want to save and display any string in the list box to let the users know that the corresponding functions have been enlisted and ready to run. For example, save a string "Function1 aug1 aug2 aug3" or "Funtion2 aug1 aug2" or whatever you like as a handle of the corresponding function.
And for the controller part, write a function (let's say conductor()). It reads the handle strings from the list, parses them and calls the corresponding functions. Where you want to run the enlisted functions, there you just call conductor().
Update:
Due to your comment I understand that you are pretty new to program. Let me show you how to write a simplest parser with your given variable names.
def run_listbox():
to_do_list = #get the list of strings
for handle_string in to_do_list:
#Let's say you got
#handle_string = "Predfined_function1 value1 value2"
#by here
handle = handle_string.split(" ")
#Split the string by space, so you got
#handle = ["Predfined_function1", "value1", "value2"]
#by here
if handle[0] == "Predfined_function1":
Predfined_function1(handle[1], handle[2]) #Call Predfined_function1(value1, value2)
elif handle[0] == "Predfined_function2":
Predfined_function2(handle[1], handle[2])
#elif ...
#...
#elif ...
#...
#elif ...
#...
This is not a perfect parser, but I hope it could let you know what does a parser look like.