How to fix “global name is not defined” in my code

Question

i'm giving a list in the function which takes the numbers and adds as more as possible in order return the higher sum possible which is smaller or even to the limit

maxsum=0
def maxDistance(lista,limit):
        global maxsum
        lista.sort(reverse=True)
        for i in range(len(lista)):
                 global mega
                 mega[i]=0
        for i in range(len(lista)):
                if lista[i]<=limit:
                        for j in range(len(lista)):
                                if i!=j:
                                        mega[i]=mega[i]+lista[j]
                                        if mega[i]>limit:
                                                mega[i]=mega[i]-lista[j]
        maxsum=max(mega)
        return maxsum
print ("Εισαγετε μια λιστα απο αποστασεις και υστερα αφου την καταχωρησετε ,καταχωρηστε εναν αριθμο ως οριο αθροισματος των προηγουμενων αποστασεων. Χωριστε τους αριθμους με κενα. ","\n")
lista=[float(x) for x in input("dose lista: ").split()]
limit=float(input("dose orio: "))
maxDistance(lista,limit)
print (maxsum)
input("press enter to continue")

Answer 1

You need to declare the variable mega before using the global keyword. I suggest:

mega = []
maxSum = 0
def foo():
    global mega
    global maxSum
    ...

As mad_ in the comment mentioned: in your case, if you're not altering the variable values, then you actually don't really need the global keyword. After declaring them before the function, you can directly reference them.