Python - call function inside class function

Question

I have a class that runs multiple functions. One of them is drawing an object on the sceen. I have another function that updates the state of the object, and based on the modified state, I have to change the color of the object. How can I call the function that draws the shape inside the function that updates the state. The code looks like this:

 class TrackCircuit:
 def __init__(self, id, name, state):
 self.id = id
 self.name = name
 self.state = state
 def draw(self, pos_x, pos_y, pos_end):
 self.pos_x = pos_x
 self.pos_y = pos_y
 self.pos_end = pos_end
 label_root_x = (pos_x + pos_end) / 2
 label_root_y = offset_top + offset_label
 global tc_width
 if self.state == "undefined":
 tc_color = color_undefined
 elif self.state == "occupied":
 tc_color = color_occupied
 canvas.create_line(pos_x, pos_y, pos_end, pos_y, width=tc_width, fill=tc_color)
 tc_label = Label(root, text="121", font = label_font, bg = label_background, fg = label_color)
 tc_label.place(x=label_root_x, y=label_root_y, anchor=CENTER)
 def update_state(self, state):
 self.state = state

I need to run draw() when state is modified through update_state().

• MisterMiyagi: So you want to call self.draw() inside update_state?
• lghh: You have to use the self parameter, which refers on the object. By calling self.ANY_METHOD() you call the method ANY_METHOD. So in your case you have to use self.draw() inside of the update_state method.
• Ahmet: Do you mean call it inside update_state ? Call it as you would normally, self.draw()

Answer 1

self it's the current instance, so you can call on it every method and access every attributes.

Therefore you simply need to call:

self.draw()

So the code becames:

def update_state(self, state):
 self.state = state
 self.draw()

Answer 2

You can call a method of the class via self like this:

class TrackCircuit:
 def __init__(self, id, name, state):
 # your code
 def draw(self, pos_x, pos_y, pos_end):
 # your code
 def update_state(self, state):
 self.state = state
 self.draw(....)

Answer 3

If you need a function to dinamically assign choices in an selectfield of WTForm you must do that outside the Class. Find out on Dynamically assign choices in an selectfield of WTForm using a FieldList