a global variable is always defined in the main function while a local one is defined in a  non-main function. A global variable can be used in either  the main function or the non-main function. However, the local variable can only be used in the defined function and can not be used in other functions.

Example-1

def age():

   age1=10

   age2=20

   Age()

   print(age1)

def Age():

   age1=20

   age2=50

age1=0

age2=1

age()

print(str(age1),str(age2))

---

outPut

10

0 1

Example-2 (the global variable can be used in a local scope if it is not defined in the local scope)

def eggs():

   print(egg)

egg=1

eggs()

print(egg)

---outPut

1

1

Example-3 (define a global variable in a local scope function)

def eggs():

   global egg

   print(egg)

   egg=2

egg=1

eggs()

print(egg)

---outPut

1

2