 # Python | Find the sum of the frequency of given items in a list

Example :

`  Input:  list1 = [1, 2, 3] list2 = [2, 1, 2, 1, 3, 5, 2, 3]  Output:  7  Explanation:  No of time 1 occurring in list2 is: 2 No of time 2 occurring in list2 is: 3 No of time 3 occurring in list2 is: 2 Sum = 2 + 3 + 2 = 7 `

Below are some ways to solve the above problems.

Method # 1: Using ` sum () `

 ` # Python code for finding the sum of frequencies ` ` # element of the first list in the second list. `   ` # Initialization list ```` Input1 = [ 1 , 2 , 3 ] Input2 = [ 2 , 1 , 2 , 1 , 3 , 5 , 2 , 3 ]    # Using sum Output = sum (Input2.count (elem) for elem in  Input1)   # Printout print ( "Initial list are:" , Input1, Input2) print ( "Frequency is:" , Output) ```

Exit:

` Initial list are: [1, 2, 3] [2, 1, 2, 1, 3, 5, 2, 3] Frequency is: 7 `

Method # 2: Using ` sum () ` and `Counter()`

 ` from ` ` collections ` ` import ` ` Counter `   ` # Init list andization ` ` Input1 ` ` = ` ` [ 1 , 2 , 3 ] ```` Input2 = [ 2 , 1 , 2 , 1 , 3 , 5 , 2 , 3 ]      temp = < / code> Counter (Input2) Output = sum (temp [x] for x in Input1)    # Printout print ( " Initial list are: " , Input1, Input2) print ( "Frequency is:" , Output) ```

Exit:

` Initial list are: [1, 2, 3] [2, 1, 2, 1, 3, 5, 2, 3] Frequency is: 7 `