Question

Python code that:
Accepts a list of integers and an integer, and returns the index of the SECOND  occurrence of the integer in the list. It returns None if the number does not occur two or more times in the list.
Example 1: second_index([2,34,3,45,34,45,3,3], 3) returns 6
Example 2: second_index([2,34,3,45,34,45,3,3], 45) returns 5
Example 3: second_index([2,34,3,45,134,45,3,3], 134) returns None
Example 4: second_index([2,34,3,45,134,45,3,3], 100) returns None

Answer 1

PYTHON

# by default function retuns the none
def second_index(lst , n):
c = 0
#runs the loop
for i in range(len(lst)):
# checks the condition for integer
if(lst[i] == n):
# when integer finds out in the list c is increment
c+=1
#checks the
if(c==2):
# when integer finds for 2nd time then return then index of
return i
  
#calling a fucntion & passing the parameters & returned value is stored into res variable
res = second_index([2,34,3,45,34,45,3,3],3)
#printing the returned value of function
print(res)

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