In [14]:
list1 = [5, 10, 15, 20, 25, 50, 20]

list1.remove(20)
list1.insert(3,200)
print(list1)
    

[5, 10, 15, 200, 25, 50, 20]
In [21]:
list1 = [5, 20, 15, 20, 25, 50, 20]
    
list(filter(lambda a:a!=20, list1))
Out[21]:
[5, 15, 25, 50]
In [44]:
list1 = [10, 20, 30, 40]
list2 = [100, 200, 300, 400]

for x,y in zip(list1, reversed(list2)) :
    print (x,y)
 

10 400
20 300
30 200
40 100
In [ ]: