why x still undefined?

Question

from tkinter import *
z= {'black':1, 'red':2,'yellow':3,'blue':4,'red':5}
co=list(z)
v=[]
ls=[]
w = Tk()
g=Label(w,text=' ',width=10,height=5)
g.pack()
c=0
def f():
global x
global c
m=co[c%len(co)]
g.config(bg=m)
a=z.get(m)
v.append(str(a))
w.after(1000,f)
c+=1
if c==5 :
g.pack_forget()

x=''.join(v)

f()

b1=Button(w,text='',width=8,height=5,bg='black',command=lambda:ls.append(1)).pack(side=LEFT)
b2=Button(w,text='',width=8,height=5,bg='red',command=lambda:ls.append(2)).pack(side=LEFT)
b3=Button(w,text='',width=8,height=5,bg='yellow',command=lambda:ls.append(3)).pack(side=LEFT)
b4=Button(w,text='',width=8,height=5,bg='blue',command=lambda:ls.append(4)).pack(side=LEFT)
def check():
global x
if ls==x:
print(x)

Button(w,text='check',command=check).pack()
w.mainloop()

Answer 1

What do I do to make x defined

Answer 2

X =". Join(v) in the last line of f ()function I wanna use this value in check function how to do that

Answer 3

Just declare
global x
x = 0
At the start of the file. Global functions inside functions can make changes to already globally declared variables.

Answer 4

the same way to define any variable ? What is “x” intended to be?

there must be an x outside the scope.

Answer 5

ok. That declaration must be outside of f(). The use of global is to modify variables outside of the scope