Can someone explain?


#1



My code is absolutely working but i don't understand why we are using a comma after index and two variable names(index and item) where should be only one.
And kindly explain enumerate.
Thankyou


Replace this line with your code. 
choices = ['pizza', 'pasta', 'salad', 'nachos']

print 'Your choices are:'
for index, item in enumerate(choices):
    print index+1, item


#2

Tuples and lists, perhaps other kinds of values as well, can be unpacked:

a = 4
b = 1
a, b = b, a
print a, b  # 1 4
c = b, a
a, b = c
print a, b  # 4 1

def add(a, b): return a + b

print add(*c)  # 5 (unpacked c into two arguments)

(the value b, a is a tuple)

enumerate is described here:
https://docs.python.org/2/library/functions.html#enumerate