Global Variable Error

Question

   stack = ['','','','','','']
   global first
   global last
   first = 0
   last = 0
   print(stack)
   while True:
       def push():
           if 0 <= last:
               stack[last] = 'D'
               last = last + 1
               if last == 6:
               last = -1
           else:
               print("The stack is full.")
               print(stack)
        def pop():
           stack[last] = ''
           last == stack[last-1]
           print(stack)
           if first == last:
               print("The queue is empty")
       a = input("Push or pop. ")
       if a == 'push':
           push()
       elif a == 'pop':
           pop()

I've assigned last as a global variable yet I get this error UnboundLocalError: local variable 'last' referenced before assignment. Considering I've made last a global variable I don't understand why the error is suggesting otherwise, any solutions?

Don't define functions inside loops. Don't use `global`. Don't preallocate lists. — Daniel, Nov 24 '16 at 18:38
I know the use of global variables is bad practice, but why can't it call the global variable from within the loop? @Daniel — Joseph, Nov 24 '16 at 18:43

score -1 · Answer 1 · edited May 23 '17 at 11:59

-1

The global must be inside the def. Using global variables in a function other than the one that created them

edited May 23 '17 at 11:59

Community

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answered Nov 24 '16 at 18:37

Waxrat

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Global Variable Error

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